Web Cryptography API

1. Introduction

This section is non-normative.

The Web Cryptography API defines a low-level interface to interacting with cryptographic key material that is managed or exposed by user agents. The API itself is agnostic of the underlying implementation of key storage, but provides a common set of interfaces that allow rich web applications to perform operations such as signature generation and verification, hashing and verification, encryption and decryption, without requiring access to the raw keying material.

Cryptographic transformations are exposed via the SubtleCrypto interface, which defines a set of methods for performing common cryptographic operations. In addition to operations such as signature generation and verification, hashing and verification, and encryption and decryption, the API provides interfaces for key generation, key derivation and key import and export.

2. Use Cases

This section is non-normative.

2.1. Multi-factor Authentication

A web application may wish to extend or replace existing username/password based authentication schemes with authentication methods based on proving that the user has access to some secret keying material. Rather than using transport-layer authentication, such as TLS client certificates, the web application may prefer the richer user experience provided by authenticating within the application itself.

Using the Web Cryptography API, the application could locate suitable client keys, which may have been previously generated via the user agent or pre-provisioned out-of-band by the web application. It could then perform cryptographic operations such as decrypting an authentication challenge followed by signing an authentication response.

This exchange could be further strengthened by binding the authentication to the TLS session over which the client is authenticating, by deriving a key based on properties of the underlying transport.

If a user does not already have a key associated with their account, the web application could direct the user agent to either generate a new key or to re-use an existing key of the user's choice.

2.2. Protected Document Exchange

A web application may wish to limit the viewership of documents that contain sensitive or personal information, even when these documents have been securely received, such as over TLS.

Using the Web Cryptography API, the application could do so by encrypting the documents with a secret key, and then wrapping that key with the public keys associated with the authorized viewers. When a user agent navigates to such a web application, the application would send the encrypted form of the document. The user agent is then instructed to unwrap the encryption key, using the user's private key, and from there, decrypt and display the document.

2.3. Cloud Storage

A web application may wish to permit users to protect the confidentiality of data and documents stored with remote service providers prior to uploading.

Using the Web Cryptography API, the application may have a user select a private or secret key, optionally derive an encryption key from the selected key, encrypt the document, and then upload the encrypted data to the service provider using existing APIs.

This use case is similar to the Protected Document Exchange use case, with viewership of the document limited to the user themself.

2.4. Document Signing

A web application may wish to accept electronic signatures on documents, in lieu of requiring physical signatures.

Using the Web Cryptography API, the application may direct the user to select a key, which may have been pre-provisioned out-of-band, or generated specifically for the web application. Using this key, the application may perform a signing operation over some data, as proof that the user accepts the document.

2.5. Data Integrity Protection

A web application may wish to cache data locally, while ensuring that this data cannot be modified in an offline attack.

Using the Web Cryptography API, the application may use a public key contained within the application to verify the contents of the data cache. Previously, when data was added to the cache, it would have been signed by the server with the corresponding private key. By validating the signature when restoring data from the cache, the client ensures that the cached data has not been tampered with.

2.6. Secure Messaging

A web application may wish to employ message layer security using schemes such as off-the-record (OTR) messaging, even when these messages have been securely received, such as over TLS.

The Web Cryptography API enables OTR and similar message signing schemes, by allowing key agreement to be performed. The two parties can negotiate shared encryption keys and message authentication code (MAC) keys, to allow encryption and decryption of messages, and to prevent tampering.

2.7. JavaScript Object Signing and Encryption (JOSE)

A web application may wish to interact with the structures and message formats defined by the IETF JavaScript Object Signing and Encryption (JOSE) Working Group.

Using the Web Cryptography API, the application may read and import keys encoded in the JSON key format (JWK), validate messages that have been integrity protected using digital signatures or MACs (JWS), or decrypt messages that have been encrypted (JWE).

3. Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.

The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, RECOMMENDED, MAY, OPTIONAL, in this specification are to be interpreted as described in Key words for use in RFCs to Indicate Requirement Levels [RFC2119].

The following conformance classes are defined by this specification:

conforming user agent: A user agent is considered to be a conforming user agent if it satisfies all of the MUST-, REQUIRED- and SHALL-level criteria in this specification that apply to implementations. This specification uses both the terms "conforming user agent" and "user agent" to refer to this product class.

Conformance requirements phrased as algorithms or specific steps may be implemented in any manner, so long as the end result is equivalent. (In particular, the algorithms defined in this specification are intended to be easy to follow, and not intended to be performant.)

User agents that use ECMAScript to implement the APIs defined in this specification MUST implement them in a manner consistent with the ECMAScript Bindings defined in the Web IDL specification [WebIDL] as this specification uses that specification and terminology.

Unless otherwise stated, string comparisons are done in a case-sensitive manner. String literals in this specification written in monospace font like "this" do not include the enclosing quotes.

3.1. Extensibility

Vendor-specific proprietary extensions to this specification are strongly discouraged. Authors must not use such extensions, as doing so reduces interoperability and fragments the user base, allowing only users of specific user agents to access the content in question.

If vendor-specific extensions are needed, the members should be prefixed by vendor-specific strings to prevent clashes with future versions of this specification. Extensions must be defined so that the use of extensions neither contradicts nor causes the non-conformance of functionality defined in the specification.

When vendor-neutral extensions to this specification are needed, either this specification can be updated accordingly, or an extension specification can be written that overrides the requirements in this specification. When someone applying this specification to their activities decides that they will recognize the requirements of such an extension specification, it becomes an applicable specification for the purposes of conformance requirements in this specification. Applicable specifications defined by the W3C Web Cryptography Working Group are listed in the table below.

Specification

Reference

Note

Readers are advised to consult the errata to this specification for updates to the table above.

4. Scope

This section is non-normative.

4.1. Level of abstraction

The specification attempts to focus on the common functionality and features between various platform-specific or standardized cryptographic APIs, and avoid features and functionality that are specific to one or two implementations. As such this API allows key generation, management, and exchange with a level of abstraction that avoids developers needing to care about the implementation of the underlying key storage. The API is focused specifically around CryptoKey objects, as an abstraction for the underlying raw cryptographic keying material. The intent behind this is to allow an API that is generic enough to allow conforming user agents to expose keys that are stored and managed directly by the user agent, that may be stored or managed using isolated storage APIs such as per-user key stores provided by some operating systems, or within key storage devices such as secure elements, while allowing rich web applications to manipulate the keys and without requiring the web application be aware of the nature of the underlying key storage.

4.2. Cryptographic algorithms

Because the underlying cryptographic implementations will vary between conforming user agents, and may be subject to local policy, including but not limited to concerns such as government or industry regulation, security best practices, intellectual property concerns, and constrained operational environments, this specification does not dictate a mandatory set of algorithms that MUST be implemented. Instead, it defines a common set of bindings that can be used in an algorithm-independent manner, a common framework for discovering if a user agent or key handle supports the underlying algorithm, and a set of conformance requirements for the behaviors of individual algorithms, if implemented.

4.3. Out of scope

This API, while allowing applications to generate, retrieve, and manipulate keying material, does not specifically address the provisioning of keys in particular types of key storage, such as secure elements or smart cards. This is due to such provisioning operations often being burdened with vendor-specific details that make defining a vendor-agnostic interface an unsuitably unbounded task. Additionally, this API does not deal with or address the discovery of cryptographic modules, as such concepts are dependent upon the underlying user agent and are not concepts that are portable between common operating systems, cryptographic libraries, and implementations.

5. Concepts

This section is non-normative.

5.1. Underlying Cryptographic Implementation

This specification assumes, but does not require, that conforming user agents do not and will not be directly implementing cryptographic operations within the user agent itself. Historically, many user agents have deferred cryptographic operations, such as those used within TLS, to existing APIs that are available as part of the underlying operating system or to third-party modules that are managed independently of the user agent.

The CryptoKey object represents the bridge between the JavaScript execution environment and these underlying libraries, through the use of the internal slot named [[handle]]. The handle represents an opaque type that is implementation specific, which may not be represented within a JavaScript type, nor is it ever exposed to script authors. In this way, the CryptoKey object is the conceptual equivalent to the JavaScript executing environment as the [[handle]] is to the underlying cryptographic implementation.

These APIs are traditionally built around a notion of cryptographic providers, an abstraction for a specific implementation of a set of algorithms. The operating system or library may come with a default provider, and users are frequently allowed to add additional providers, reconfigure the set of enabled algorithms, or otherwise customize how cryptographic services are provided.

While it is assumed that most user agents will be interacting with a cryptographic provider that is implemented purely in software, it is not required by this specification. As a result, the capabilities of some implementations may be limited by the capabilities of the underlying hardware, and, depending on how the user has configured the underlying cryptographic library, this may be entirely opaque to the User Agent.

5.2. Key Storage

This specification does not explicitly provide any new storage mechanisms for CryptoKey objects. Instead, by allowing the CryptoKey to be used with the structured clone algorithm, any existing or future web storage mechanisms that support storing structured clonable objects can be used to store CryptoKey objects.

In practice, it is expected that most authors will make use of the Indexed Database API, which allows associative storage of key/value pairs, where the key is some string identifier meaningful to the application, and the value is a CryptoKey object. This allows the storage and retrieval of key material, without ever exposing that key material to the application or the JavaScript environment. Additionally, this allows authors the full flexibility to store any additional metadata with the CryptoKey itself.

6. Security considerations

This section is non-normative.

6.1. Security considerations for implementers

By not providing an explicit storage mechanism, this specification assumes that CryptoKey objects are scoped to the current execution environment and any storage mechanisms available to that environment (e.g. Indexed Database API). Application authors rely upon this for the security of their applications; two origins with the same CryptoKey object have full access to the underlying key, and as such, messages from these applications cannot be distinguished, and messages sent to these applications can be fully recovered. Implementors should ensure that no CryptoKey objects are shared between two origins unless the author has explicitly chosen to share (e.g., such as through the use of postMessage)

A number of algorithms specified within this specification perform computationally intensive work, such as the generation of significantly large prime numbers, or through repeated iterations of a particular operation. As such, hostile applications may attempt to misuse this API and attempt to cause significant amount of work to be performed by an implementation, denying access or services to other applications that are executing. Implementations should take steps to mitigate these risks, such as limiting the amount of operations an implementation performs concurrently, requiring user consent for operations that may be known to be disruptive for the executing environment, or defining device-specific limits on attributes such as key sizes or iteration counts.

6.2. Security considerations for authors

This specification includes descriptions for a variety of cryptographic operations, some of which have known weaknesses when used inappropriately. Application developers must take care and review appropriate and current cryptographic literature, to understand and mitigate such issues. In general, application developers are strongly discouraged from inventing new cryptographic protocols; as with all applications, users of this specification will be best served through the use of existing protocols, of which this specification provides the necessary building blocks to implement.

In order to use the APIs defined in this specification to provide any meaningful cryptographic assurances, authors must be familiar with existing threats to web applications, as well as the underlying security model employed. Conceptually, issues such as script injection are the equivalent to remote code execution in other operating environments, and allowing hostile script to be injected may allow for the exfiltration of keys or data. Script injection may come from other applications, for which the judicious use of Content Security Policy may mitigate, or it may come from hostile network intermediaries, for which the use of Transport Layer Security may mitigate.

This specification does not define any specific mechanisms for the storage of cryptographic keys. By default, unless specific effort is taken by the author to persist keys, such as through the use of the Indexed Database API, keys created with this API will only be valid for the duration of the current page (e.g. until a navigation event). Authors that wish to use the same key across different pages or multiple browsing sessions must employ existing web storage technologies. Authors should be aware of the security assumptions of these technologies, such as the same-origin security model; that is, any application that shares the same scheme, host, and port have access to the same storage partition, even if other information, such as the path, may differ. Authors may explicitly choose to relax this security through the use of inter-origin sharing, such as postMessage.

Authors should be aware that this specification places no normative requirements on implementations as to how the underlying cryptographic key material is stored. The only requirement is that key material is not exposed to script, except through the use of the exportKey and wrapKey operations. In particular, it does not guarantee that the underlying cryptographic key material will not be persisted to disk, possibly unencrypted, nor that it will be inaccessible to users or other applications running with the same privileges as the User Agent. Any application or user that has access to the device storage may be able to recover the key material, even through scripts may be prohibited.

This specification places no normative requirements on how implementations handle key material once all references to it go away. That is, conforming user agents are not required to zeroize key material, and it may still be accessible on device storage or device memory, even after all references to the CryptoKey have gone away.

Applications may share a CryptoKey object across security boundaries, such as origins, through the use of the structured clone algorithm and APIs such as postMessage. While access to the underlying cryptographic key material may be restricted, based upon the extractable attribute, once a key is shared with a destination origin, the source origin can not later restrict or revoke access to the key. As such, authors must be careful to ensure they trust the destination origin to take the same mitigations against hostile script that the source origin employs. Further, in the event of script injection on the source origin, attackers may post the key to an origin under attacker control. Any time that the user agent visits the attacker's origin, the user agent may be directed to perform cryptographic operations using that key, such as the decryption of existing messages or the creation of new, fraudulent messages.

Authors should be aware that users may, at any time, choose to clear the storage associated with an origin, potentially destroying keys. Applications that are meant to provide long-term storage, such as on the server, should consider techniques such as key escrow to prevent such data from being inaccessible. Authors should not presume that keys will be available indefinitely.

6.3. Security considerations for users

Users of applications that employ the APIs defined in this specification should be aware that these applications will have full access to all messages exchanged, regardless of the cryptography employed. That is, for messages that are encrypted, applications that use these APIs will have full access to the decrypted message as well.

7. Privacy considerations

This section is non-normative.

Fingerprinting: By exposing additional APIs that reflect capabilities of the underlying platform, this specification may allow malicious applications to determine or distinguish different user agents or devices.
Super-cookies: This specification does not provide any means for malicious applications to create identifiers that outlive existing web storage technologies. However, care must be taken when introducing future revisions to this API or additional cryptographic capabilities, such as those that are hardware backed (e.g.: smart cards or Trusted Platform Modules). Considering that such storage is designed to prevent any two users from having the same underlying key data, such APIs may represent a real risk of being used as a permanent identifier against the user's wishes.

8. Dependencies

This specification relies on underlying specifications.

DOM: A conforming user agent MUST support at least the subset of the functionality defined in DOM4 that this specification relies upon; in particular, it MUST support Promises and DOMException. [DOM4]
HTML: A conforming user agent MUST support at least the subset of the functionality defined in HTML that this specification relies upon; in particular, it MUST support the ArrayBufferView typedef and the structured clone algorithm. [HTML]
Web IDL: A conforming user agent MUST be a conforming implementation of the IDL fragments in this specification, as described in the Web IDL specification. [WebIDL]

9. Terminology

The terms and algorithms ArrayBuffer, ArrayBufferView, and structured clone, are defined by the HTML specification [HTML].

The terms DOMString and BufferSource are defined in [WebIDL].

An octet string is an ordered sequence of zero or more integers, each in the range 0 to 255 inclusive.

An octet string containing a bit string b is the octet string obtained by first appending zero or more bits of value zero to b such that the length of the resulting bit string is minimal and an integer multiple of 8 and then considering each consecutive sequence of 8 bits in that string as a binary integer, most significant bit first.

When this specification says to convert a non-negative integer i to an octet string of length n, where n * 8 is greater than the logarithm to base 2 of i, the user agent must first calculate the binary representation of i, most significant bit first, prefix this with sufficient zero bits to form a bit string of length n * 8, and then return the octet string formed by considering each consecutive sequence of 8 bits in that bit string as a binary integer, most significant bit first.

Comparing two strings in a case-sensitive manner means comparing them exactly, code point for code point.

Comparing two strings in a ASCII case-insensitive manner means comparing them exactly, code point for code point, except that the codepoints in the range U+0041 .. U+005A (i.e. LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and the corresponding codepoints in the range U+0061 .. U+007A (i.e. LATIN SMALL LETTER A to LATIN SMALL LETTER Z) are also considered to match.

When this specification says to terminate the algorithm, the user agent must terminate the algorithm after finishing the step it is on. The algorithm referred to is the set of specification-defined processing steps, rather than the underlying cryptographic algorithm that may be in the midst of processing.

When this specification says to parse an ASN.1 structure, the user agent must perform the following steps:

Let data be a sequence of bytes to be parsed.
Let structure be the ASN.1 structure to be parsed.
Let exactData be an optional boolean value. If it is not supplied, let it be initialized to true.
Parse data according to the Distinguished Encoding Rules of X.690 (11/08), using structure as the ASN.1 structure to be decoded.
If exactData was specified, and all of the bytes of data were not consumed during the parsing phase, then throw a DataError.
Return the parsed ASN.1 structure.

When this specification says to parse a subjectPublicKeyInfo, the user agent must parse an ASN.1 structure, with data set to the sequence of bytes to be parsed, structure as the ASN.1 structure of subjectPublicKeyInfo, as specified in RFC 5280, and exactData set to true.

When this specification says to parse a PrivateKeyInfo, the user agent must parse an ASN.1 structure with data set to the sequence of bytes to be parsed, structure as the ASN.1 structure of PrivateKeyInfo, as specified in RFC 5208, and exactData set to true.

When this specification says to parse a JWK, the user agent must run the following steps:

Let data be the sequence of bytes to be parsed.
Let json be the Unicode string that results from interpreting data according to UTF-8.
Convert json to UTF-16.
Let result be the object literal that results from executing the JSON.parse internal function in the context of a new global object, with text argument set to a JavaScript String containing json.
Let key be the result of converting result to the IDL dictionary type of JsonWebKey.
If the "kty" field of key is not defined, then throw a DataError.
Return key.

When this specification states to supply the contents of an ArrayBuffer named data to an underlying cryptographic implementation, the User Agent shall supply a contiguous sequence of bytes that is equal to the result of geting a copy of the bytes held data.

When this specification says to calculate the usage intersection of two sequences, a and b the result shall be a sequence containing each recognized key usage value that appears in both a and b, in the order listed in the list of recognized key usage values, where a value is said to appear in a sequence if an element of the sequence exists that is a case-sensitive string match for that value.

When this specification says to calculate the normalized value of a usages list, usages the result shall be the usage intersection of usages and a sequence containing all recognized key usage values.

When this specification refers to the cached ECMAScript object associated with an internal slot [[slot]] of object, the user agent must run the following steps:

If the [[slot_cached]] internal slot of object is undefined:

Set the [[slot_cached]] internal slot of object to the result of performing type conversion to an ECMAScript object as defined in [WebIDL] to the contents of the [[slot]] internal slot of object.
Return the contents of the [[slot_cached]] internal slot of object.

10. Crypto interface

IDL


[NoInterfaceObject,Exposed=(Window,Worker)]
interface GlobalCrypto {
  readonly attribute Crypto crypto;
};

Window implements GlobalCrypto;
WorkerGlobalScope implements GlobalCrypto;        
        
[Exposed=(Window,Worker)]
interface Crypto {
  [SecureContext] readonly attribute SubtleCrypto subtle;
  ArrayBufferView getRandomValues(ArrayBufferView array);
};

10.1. Description

This section is non-normative.

The Crypto interface represents an interface to general purpose cryptographic functionality including a cryptographically strong pseudo-random number generator seeded with truly random values.

Note

Implementations should generate cryptographically random values using well-established cryptographic pseudo-random number generators seeded with high-quality entropy, such as from an operating-system entropy source (e.g., "/dev/urandom"). This specification provides no lower-bound on the information theoretic entropy present in cryptographically random values, but implementations should make a best effort to provide as much entropy as practicable.

Note

This interface defines a synchronous method for obtaining cryptographically random values. While some devices and implementations may support truly random cryptographic number generators or provide interfaces that block when there is insufficient entropy, implementations are discouraged from using these sources when implementing getRandomValues, both for performance and to avoid depleting the system of entropy. Instead, these sources should be used to seed a cryptographic pseudo-random number generator that can then return suitable values efficiently.

10.2. Methods and Parameters

10.2.1. The getRandomValues method

The getRandomValues method generates cryptographically random values. It must act as follows:

If array is not of an integer type (i.e., Int8Array, Uint8Array, Int16Array, Uint16Array, Int32Array, Uint32Array or UInt8ClampedArray), throw a TypeMismatchError and terminate the algorithm.
If the byteLength of array is greater than 65536, throw a QuotaExceededError and terminate the algorithm.
Overwrite all elements of array with cryptographically random values of the appropriate type.
Return array.

Note

Do not generate keys using the getRandomValues method. Use the generateKey method instead.

10.3. Attributes

10.3.1. The subtle attribute

The subtle attribute provides an instance of the SubtleCrypto interface which provides low-level cryptographic primitives and algorithms.

11. Algorithm dictionary

The Algorithm object is a dictionary object [WebIDL] which is used to specify an algorithm and any additional parameters required to fully specify the desired operation.

IDL


typedef (object or DOMString) AlgorithmIdentifier;

typedef AlgorithmIdentifier HashAlgorithmIdentifier;

dictionary Algorithm {
  required DOMString name;
};

11.1. Algorithm Dictionary Members

name: The name of the registered algorithm to use.

12. KeyAlgorithm dictionary

The KeyAlgorithm dictionary represents information about the contents of a given CryptoKey object.

IDL


dictionary KeyAlgorithm {
  required DOMString name;
};

12.1. Description

This section is non-normative.

The KeyAlgorithm dictionary is provided to aid in documenting how fixed, public properties of a CryptoKey are reflected back to an application. The actual dictionary type is never exposed to applications.

12.2. KeyAlgorithm dictionary members

name: The name of the algorithm used to generate the CryptoKey

13. CryptoKey interface

The CryptoKey object represents an opaque reference to keying material that is managed by the user agent.

IDL


enum KeyType { "public", "private", "secret" };

enum KeyUsage { "encrypt", "decrypt", "sign", "verify", "deriveKey", "deriveBits", "wrapKey", "unwrapKey" };

[SecureContext,Exposed=(Window,Worker)]
interface CryptoKey {
  readonly attribute KeyType type;
  readonly attribute boolean extractable;
  readonly attribute object algorithm;
  readonly attribute object usages;
};

13.1. Description

This section is non-normative.

This specification provides a uniform interface for many different kinds of keying material managed by the user agent. This may include keys that have been generated by the user agent, derived from other keys by the user agent, imported to the user agent through user actions or using this API, pre-provisioned within software or hardware to which the user agent has access or made available to the user agent in other ways. The term key refers broadly to any keying material including actual keys for cryptographic operations and secret values obtained within key derivation or exchange operations.

The CryptoKey object is not required to directly interface with the underlying key storage mechanism, and may instead simply be a reference for the user agent to understand how to obtain the keying material when needed, e.g. when performing a cryptographic operation.

13.2. Key interface data types

KeyType: The type of a key. The recognized key type values are "public", "private" and "secret". Opaque keying material, including that used for symmetric algorithms, is represented by "secret", while keys used as part of asymmetric algorithms composed of public/private keypairs will be either "public" or "private".
KeyUsage: A type of operation that may be performed using a key. The recognized key usage values are "encrypt", "decrypt", "sign", "verify", "deriveKey", "deriveBits", "wrapKey" and "unwrapKey".

13.3. CryptoKey internal slots

Every CryptoKey object has a set of internal slots that store information about the key. These slots are not exposed as part of this specification; they represent internal state that an implementation uses to implement this specification. The notational convention used in [ECMA-262] is re-used here; internal slots are identified by names enclosed in double square brackets [[ ]].

All CryptoKey objects have internal slots named [[type]], [[extractable]], [[algorithm]], [[algorithm_cached]], [[usages]], [[usages_cached]], and [[handle]].

The contents of the [[algorithm]] internal slot shall be, or be derived from, a KeyAlgorithm. The contents of the [[usages]] internal slot shall be of type Sequence<KeyUsage>.

The [[handle]] slot is an opaque type that contains whatever data the underlying cryptographic implementation uses to represent a logical key. Different cryptographic implementations may use different types, ranging from opaque identifiers represented as integers, pointer types, or structures that provide identifying information. These handles are never exposed to applications.

13.4. CryptoKey interface members

type: Reflects the [[type]] internal slot, which contains the type of the underlying key.
extractable: Reflects the [[extractable]] internal slot, which indicates whether or not the raw keying material may be exported by the application.
algorithm: Returns the cached ECMAScript object associated with the [[algorithm]] internal slot.
usages: Returns the cached ECMAScript object associated with the [[usages]] internal slot, which indicates which cryptographic operations are permissible to be used with this key.

13.5. Structured clone algorithm

When a user agent is required to obtain a structured clone of a CryptoKey object, it must run the following steps.

Let input and memory be the corresponding inputs defined by the internal structured cloning algorithm, where input represents a CryptoKey object to be cloned.
Let output be a newly constructed CryptoKey object.
Let the [[type]], [[extractable]], [[algorithm]], and [[usages]] internal slots of output be set to the result of invoking the internal structured clone algorithm recursively on the corresponding internal slots of input, with the slot contents as the new "input" argument and memory as the new "memory" argument.
Let the [[handle]] internal slot of output refer to the same cryptographic key data represented by the [[handle]] internal slot of input.

Note

When performing the structured clone algorithm in order to serialize a CryptoKey object, implementations must not allow the object to be deserialized as a different type. This is normatively required by the definition of structured clone, but it merits specific attention, as such deserialization may expose the contents of the [[handle]] internal slot, which in some implementations may contain cryptographic key data that should not be exposed to applications.

14. SubtleCrypto interface

IDL


enum KeyFormat { "raw", "spki", "pkcs8", "jwk" };

[SecureContext,Exposed=(Window,Worker)]
interface SubtleCrypto {
  Promise<any> encrypt(AlgorithmIdentifier algorithm,
                       CryptoKey key,
                       BufferSource data);
  Promise<any> decrypt(AlgorithmIdentifier algorithm,
                       CryptoKey key,
                       BufferSource data);
  Promise<any> sign(AlgorithmIdentifier algorithm,
                    CryptoKey key,
                    BufferSource data);
  Promise<any> verify(AlgorithmIdentifier algorithm,
                      CryptoKey key,
                      BufferSource signature,
                      BufferSource data);
  Promise<any> digest(AlgorithmIdentifier algorithm,
                      BufferSource data);

  Promise<any> generateKey(AlgorithmIdentifier algorithm,
                          boolean extractable,
                          sequence<KeyUsage> keyUsages );
  Promise<any> deriveKey(AlgorithmIdentifier algorithm,
                         CryptoKey baseKey,
                         AlgorithmIdentifier derivedKeyType,
                         boolean extractable,
                         sequence<KeyUsage> keyUsages );
  Promise<ArrayBuffer> deriveBits(AlgorithmIdentifier algorithm,
                          CryptoKey baseKey,
                          unsigned long length);
  
  Promise<CryptoKey> importKey(KeyFormat format,
                         (BufferSource or JsonWebKey) keyData,
                         AlgorithmIdentifier algorithm,
                         boolean extractable,
                         sequence<KeyUsage> keyUsages );
  Promise<any> exportKey(KeyFormat format, CryptoKey key);

  Promise<any> wrapKey(KeyFormat format,
                       CryptoKey key,
                       CryptoKey wrappingKey,
                       AlgorithmIdentifier wrapAlgorithm);
  Promise<CryptoKey> unwrapKey(KeyFormat format,
                         BufferSource wrappedKey,
                         CryptoKey unwrappingKey,
                         AlgorithmIdentifier unwrapAlgorithm,
                         AlgorithmIdentifier unwrappedKeyAlgorithm,
                         boolean extractable,
                         sequence<KeyUsage> keyUsages );
};

14.1. Description

This section is non-normative.

The SubtleCrypto interface provides a set of methods for dealing with low-level cryptographic primitives and algorithms. It is named SubtleCrypto to reflect the fact that many of these algorithms have subtle usage requirements in order to provide the required algorithmic security guarantees.

For example, the direct use of an unauthenticated encryption scheme, such as AES in counter mode, gives potential attackers the ability to manipulate bits in the output by manipulating bits in the input, compromising the integrity of the message. However, AES-CTR can be used securely in combination with other cryptographic primitives, such as message authentication codes, to ensure the integrity of the protected message, but only when the message authentication code is constructed over the encrypted message and IV.

Developers making use of the SubtleCrypto interface are expected to be aware of the security concerns associated with both the design and implementation of the various algorithms provided. The raw algorithms are provided in order to allow developers maximum flexibility in implementing a variety of protocols and applications, each of which may represent the composition and security parameters in a unique manner that necessitate the use of the raw algorithms.

14.2. Data Types

KeyFormat

Specifies a serialization format for a key. The recognized key format values are:

"raw": An unformatted sequence of bytes. Intended for secret keys.
"pkcs8": The DER encoding of the PrivateKeyInfo structure from RFC 5208.
"spki": The DER encoding of the SubjectPublicKeyInfo structure from RFC 5280.
"jwk": The key is a JsonWebKey dictionary encoded as a JavaScript object

14.3. Methods and Parameters

Unless otherwise stated, objects created by the methods defined in this section shall be associated with the relevant global object of this [HTML].

Note

All errors are reported asynchronously by rejecting the returned Promise. This includes Web IDL type mapping errors.

14.3.1. The encrypt method

The encrypt method returns a new Promise object that will encrypt data using the specified AlgorithmIdentifier with the supplied CryptoKey. It must act as follows:

Let algorithm and key be the algorithm and key parameters passed to the encrypt method, respectively.
Let data be the result of getting a copy of the bytes held by the data parameter passed to the encrypt method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "encrypt".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of key then throw an InvalidAccessError.
If the [[usages]] internal slot of key does not contain an entry that is "encrypt", then throw an InvalidAccessError.
Let ciphertext be the result of performing the encrypt operation specified by normalizedAlgorithm using algorithm and key and with data as plaintext.
Resolve promise with ciphertext.

14.3.2. The decrypt method

The decrypt method returns a new Promise object that will decrypt data using the specified AlgorithmIdentifier with the supplied CryptoKey. It must act as follows:

Let algorithm and key be the algorithm and keyparameters passed to the decrypt method, respectively.
Let data be the result of getting a copy of the bytes held by the data parameter passed to the decrypt method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "decrypt".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of key then throw an InvalidAccessError.
If the [[usages]] internal slot of key does not contain an entry that is "decrypt", then throw an InvalidAccessError.
Let plaintext be the result of performing the decrypt operation specified by normalizedAlgorithm using key and algorithm and with data as ciphertext.
Resolve promise with plaintext.

14.3.3. The sign method

The sign method returns a new Promise object that will sign data using the specified AlgorithmIdentifier with the supplied CryptoKey. It must act as follows:

Let algorithm and key be the algorithm and key parameters passed to the sign method, respectively.
Let data be the result of getting a copy of the bytes held by the data parameter passed to the sign method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "sign".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of key then throw an InvalidAccessError.
If the [[usages]] internal slot of key does not contain an entry that is "sign", then throw an InvalidAccessError.
Let result be the result of performing the sign operation specified by normalizedAlgorithm using key and algorithm and with data as message.
Resolve promise with result.

14.3.4. The verify method

The verify method returns a new Promise object that will verify data using the specified AlgorithmIdentifier with the supplied CryptoKey. It must act as follows:

Let algorithm and key be the algorithm and key parameters passed to the verify method, respectively.
Let signature be the result of getting a copy of the bytes held by the signature parameter passed to the verify method.
Let data be the result of getting a copy of the bytes held by the data parameter passed to the verify method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "verify".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of key then throw an InvalidAccessError.
If the [[usages]] internal slot of key does not contain an entry that is "verify", then throw an InvalidAccessError.
Let result be the result of performing the verify operation specified by normalizedAlgorithm using key, algorithm and signature and with data as message.
Resolve promise with result.

14.3.5. The digest method

The digest method returns a new Promise object that will digest data using the specified AlgorithmIdentifier. It must act as follows:

Let algorithm be the algorithm parameter passed to the digest method.
Let data be the result of getting a copy of the bytes held by the data parameter passed to the digest method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "digest".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
Let result be the result of performing the digest operation specified by normalizedAlgorithm using algorithm, with data as message.
Resolve promise with result.

14.3.6. The generateKey method

When invoked, generateKey MUST perform the following steps:

Let algorithm, extractable and usages be the algorithm, extractable and keyUsages parameters passed to the generateKey method, respectively.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "generateKey".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
Let result be the result of performing the generate key operation specified by normalizedAlgorithm using algorithm, extractable and usages.
If result is a CryptoKey object:

If the [[type]] internal slot of result is "secret" or "private" and usages is empty, then throw a SyntaxError.

If result is a CryptoKeyPair object:

If the [[usages]] internal slot of the privateKey attribute of result is the empty sequence, then throw a SyntaxError.
Resolve promise with result.

14.3.7. The deriveKey method

When invoked, deriveKey MUST perform the following steps:

Let algorithm, baseKey, derivedKeyType, extractable and usages be the algorithm, baseKey, derivedKeyType, extractable and keyUsages parameters passed to the deriveKey method, respectively.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "deriveBits".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let normalizedDerivedKeyAlgorithmImport be the result of normalizing an algorithm, with alg set to derivedKeyType and op set to "importKey".
If an error occurred, return a Promise rejected with normalizedDerivedKeyAlgorithmImport.
Let normalizedDerivedKeyAlgorithmLength be the result of normalizing an algorithm, with alg set to derivedKeyType and op set to "get key length".
If an error occurred, return a Promise rejected with normalizedDerivedKeyAlgorithmLength.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of baseKey then throw an InvalidAccessError.
If the [[usages]] internal slot of baseKey does not contain an entry that is "deriveKey", then throw an InvalidAccessError.
Let length be the result of performing the get key length algorithm specified by normalizedDerivedKeyAlgorithmLength using derivedKeyType.
Let secret be the result of performing the derive bits operation specified by normalizedAlgorithm using key, algorithm and length.
Let result be the result of performing the import key operation specified by normalizedDerivedKeyAlgorithmImport using "raw" as format, secret as keyData, derivedKeyType as algorithm and using extractable and usages.
If the [[type]] internal slot of result is "secret" or "private" and usages is empty, then throw a SyntaxError.
Resolve promise with result.

14.3.8. The deriveBits method

When invoked, deriveBits MUST perform the following steps:

Let algorithm, baseKey and length, be the algorithm, baseKey and length parameters passed to the deriveBits method, respectively.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "deriveBits".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise object.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of baseKey then throw an InvalidAccessError.
If the [[usages]] internal slot of baseKey does not contain an entry that is "deriveBits", then throw an InvalidAccessError.
Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing the result of performing the derive bits operation specified by normalizedAlgorithm using baseKey, algorithm and length.
Resolve promise with result.

14.3.9. The importKey method

When invoked, the importKey method MUST perform the following steps:

Let format, algorithm, extractable and usages, be the format, algorithm, extractable and keyUsages parameters passed to the importKey method, respectively.
If format is equal to the string "raw", "pkcs8", or "spki":
1. If the keyData parameter passed to the importKey method is a JsonWebKey dictionary, throw a TypeError.
2. Let keyData be the result of getting a copy of the bytes held by the keyData parameter passed to the importKey method.
If format is equal to the string "jwk":
1. If the keyData parameter passed to the importKey method is not a JsonWebKey dictionary, throw a TypeError.
2. Let keyData be the keyData parameter passed to the importKey method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "importKey".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
Let result be the CryptoKey object that results from performing the import key operation specified by normalizedAlgorithm using keyData, algorithm, format, extractable and usages.
If the [[type]] internal slot of result is "secret" or "private" and usages is empty, then throw a SyntaxError.
Set the [[extractable]] internal slot of result to extractable.
Set the [[usages]] internal slot of result to the normalized value of usages.
Resolve promise with result.

Note

Support of "raw" key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

Note

For structured key formats, "spki", "pks8" and "jwk", fields that are not explicitly referred to in the key import procedures for an algorithm are ignored.

14.3.10. The exportKey method

When invoked, the exportKey method MUST perform the following steps:

Let format and key be the format and key parameters passed to the exportKey method, respectively.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of of the [[algorithm]] internal slot of key does not identify a registered algorithm that supports the export key operation, then throw a NotSupportedError.
If the [[extractable]] internal slot of key is false, then throw an InvalidAccessError.
Let result be the result of performing the export key operation specified by the [[algorithm]] internal slot of key using key and format.
Resolve promise with result.

Note

Support of "raw" key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

14.3.11. The wrapKey method

When invoked, the wrapKey method MUST perform the following steps:

Let format, key, wrappingKey and algorithm be the format, key, wrappingKey and wrapAlgorithm parameters passed to the wrapKey method, respectively.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "wrapKey".
If an error occurred, let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "encrypt".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of wrappingKey then throw an InvalidAccessError.
If the [[usages]] internal slot of wrappingKey does not contain an entry that is "wrapKey", then throw an InvalidAccessError.
If the algorithm identified by the [[algorithm]] internal slot of key does not support the export key operation, then throw a NotSupportedError.
If the [[extractable]] internal slot of key is false, then throw an InvalidAccessError.

Note

Because the wrapKey method effectively exports the key, only keys marked as extractable may be wrapped. In particular, this means that this API cannot create a wrapped JWK key that is marked as non-extractable using the ext JWK member.

However, the unwrapKey method does support the ext JWK member, so that wrapped non-extractable keys created elsewhere, for example by a server, can be unwrapped using this API.
Let key be the result of performing the export key operation specified the [[algorithm]] internal slot of key using key and format.
If format is equal to the strings "raw", "pkcs8", or "spki":

Set bytes be set to key.

If format is equal to the string "jwk":
1. Convert key to an ECMAScript Object, as specified in [ WebIDL], performing the conversion in the context of a new global object.
2. Let json be the result of representing key as a UTF-16 string conforming to the JSON grammar; for example, by executing the JSON.stringify algorithm specified in ECMA262 in the context of a new global object.
3. Let bytes be the byte sequence the results from converting json, a JavaScript String comprised of UTF-16 code points, to UTF-8 code points.
Note

The key wrapping operations for some algorithms place constraints on the payload size. For example AES-KW requires the payload to be a multiple of 8 bytes in length and RSA-OAEP places a restriction on the length. For key formats that offer flexibility in serialization of a given key (for example JWK), implementations may choose to adapt the serialization to the constraints of the wrapping algorithm. This is why JSON.stringify is not normatively required, as otherwise it would prohibit implementations from introducing added padding.
If normalizedAlgorithm supports the wrap key operation:

Let result be the result of performing the wrap key operation specified by normalizedAlgorithm using algorithm, wrappingKey as key and bytes as plaintext.

Otherwise, if normalizedAlgorithm supports the encrypt operation:

Let result be the result of performing the encrypt operation specified by normalizedAlgorithm using algorithm, wrappingKey as key and bytes as plaintext.

Otherwise:

throw a NotSupportedError.
Resolve promise with result.

Note

Support of "raw" key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

14.3.12. The unwrapKey method

When invoked, the unwrapKey method MUST perform the following steps:

Let format, unwrappingKey, algorithm, unwrappedKeyAlgorithm, extractable and usages, be the format, unwrappingKey, unwrapAlgorithm, unwrappedKeyAlgorithm, extractable and keyUsages parameters passed to the unwrapKey method, respectively.
Let wrappedKey be the result of getting a copy of the bytes held by the wrappedKey parameter passed to the unwrapKey method.
Let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "unwrapKey".
If an error occurred, let normalizedAlgorithm be the result of normalizing an algorithm, with alg set to algorithm and op set to "decrypt".
If an error occurred, return a Promise rejected with normalizedAlgorithm.
Let normalizedKeyAlgorithm be the result of normalizing an algorithm, with alg set to unwrappedKeyAlgorithm and op set to "importKey".
If an error occurred, return a Promise rejected with normalizedKeyAlgorithm.
Let promise be a new Promise.
Return promise and asynchronously perform the remaining steps.
If the following steps or referenced procedures say to throw an error, reject promise with the returned error and then terminate the algorithm.
If the name member of normalizedAlgorithm is not equal to the name attribute of the [[algorithm]] internal slot of unwrappingKey then throw an InvalidAccessError.
If the [[usages]] internal slot of unwrappingKey does not contain an entry that is "unwrapKey", then throw an InvalidAccessError.
If normalizedAlgorithm supports an unwrap key operation:

Let key be the result of performing the unwrap key operation specified by normalizedAlgorithm using algorithm, unwrappingKey as key and wrappedKey as ciphertext.

Otherwise, if normalizedAlgorithm supports a decrypt operation:

Let key be the result of performing the decrypt operation specified by normalizedAlgorithm using algorithm, unwrappingKey as key and wrappedKey as ciphertext.

Otherwise:

throw a NotSupportedError.
If format is equal to the strings "raw", "pkcs8", or "spki":

Set bytes be set to key.

If format is equal to the string "jwk":

Let bytes be the result of executing the parse a JWK algorithm, with key as the data to be parsed.
Let result be the result of performing the import key operation specified by normalizedKeyAlgorithm using unwrappedKeyAlgorithm as algorithm, format, usages and extractable and with bytes as keyData.
If the [[type]] internal slot of result is "secret" or "private" and usages is empty, then throw a SyntaxError.
Set the [[extractable]] internal slot of result to extractable.
Set the [[usages]] internal slot of result to the normalized value of usages.
Resolve promise with result.

Note

Support of "raw" key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

14.4. Exceptions

The methods of the SubtleCrypto interface return errors by rejecting the returned promise with a predefined exception defined in ECMAScript [ECMA-262] or DOMException. The following predefined exceptions are used: TypeError. The following DOMException types from [DOM4] are used:

Name	Description
`NotSupportedError`	The algorithm is not supported
`SyntaxError`	A required parameter was missing or out-of-range
`InvalidAccessError`	The requested operation is not valid for the provided key
`DataError`	Data provided to an operation does not meet requirements
`OperationError`	The operation failed for an operation-specific reason

When this specification says to throw an error, the user agent must throw an error as described in [WebIDL]. When this occurs in a sub-algorithm, this results in termination of execution of the sub-algorithm and all ancestor algorithms until one is reached that explicitly describes procedures for catching exceptions. The error object thrown shall be associated with the relevant global object of this [HTML].

15. JsonWebKey dictionary

IDL


dictionary RsaOtherPrimesInfo {
  // The following fields are defined in Section 6.3.2.7 of JSON Web Algorithms
  DOMString r;
  DOMString d;
  DOMString t;
};

dictionary JsonWebKey {
  // The following fields are defined in Section 3.1 of JSON Web Key
  DOMString kty;
  DOMString use;
  sequence<DOMString> key_ops;
  DOMString alg;

  // The following fields are defined in JSON Web Key Parameters Registration
  boolean ext;

  // The following fields are defined in Section 6 of JSON Web Algorithms
  DOMString crv;
  DOMString x;
  DOMString y;
  DOMString d;
  DOMString n;
  DOMString e;
  DOMString p;
  DOMString q;
  DOMString dp;
  DOMString dq;
  DOMString qi;
  sequence<RsaOtherPrimesInfo> oth;
  DOMString k;
};

Description

The following section is non-normative.

The JsonWebKey dictionary provides a way to represent and exchange cryptographic keys represented by the JSON Web Key structure, while allowing native and efficient use within Web Cryptography API applications.

16. BigInteger

IDL


typedef Uint8Array BigInteger;

The BigInteger typedef is a Uint8Array that holds an arbitrary magnitude unsigned integer in big-endian order. Values read from the API SHALL have minimal typed array length (that is, at most 7 leading zero bits, except the value 0 which shall have length 8 bits). The API SHALL accept values with any number of leading zero bits, including the empty array, which represents zero.

Note

Since the integer is unsigned, the highest order bit is NOT a sign bit. Implementors should take care when mapping to big integer implementations that expected signed integers.

17. CryptoKeyPair dictionary

IDL


dictionary CryptoKeyPair {
  CryptoKey publicKey;
  CryptoKey privateKey;
};

The CryptoKeyPair dictionary represents an asymmetric key pair that is comprised of both public and private keys.

18. Algorithms

18.1. Overview

This section is non-normative.

In addition to providing a common interface to perform cryptographic operations, by way of the SubtleCrypto interface, this specification also provides descriptions for a variety of algorithms that authors may wish to use and that User Agents may choose to implement. This includes a selection of commonly-deployed symmetric and asymmetric algorithms, key derivation mechanisms, and methods for wrapping and unwrapping keys. Further, this specification defines a process to allow additional specifications to introduce additional cryptographic algorithms.

18.2. Concepts

18.2.1. Naming

Every cryptographic algorithm defined for use with the Web Cryptography API MUST have a unique name, referred to as its recognized algorithm name, such that no other specification defines the same case-insensitive string for use with the Web Cryptography API.

18.2.2. Supported Operations

Every cryptographic algorithm defined for use with the Web Cryptography API has a list of supported operations, which are a set of sub-algorithms to be invoked by the SubtleCrypto interface in order to perform the desired cryptographic operation. This specification makes use of the following operations:

encrypt
decrypt
sign
verify
deriveBits
wrapKey
unwrapKey
generateKey
importKey
exportKey
get key length

If a given algorithm specification does not list a particular operation as supported, or explicitly lists an operation as not-supported, then the User Agent MUST behave as if the invocation of the sub-algorithm threw a NotSupportedError.

18.2.3. Normalization

Every cryptographic algorithm defined for use with the Web Cryptography API MUST define, for every supported operation, the IDL type to use for algorithm normalization, as well as the IDL type or types of the return values of the sub-algorithms.

18.3. Specification Conventions

Every cryptographic algorithm definition within this specification employs the following specification conventions. A section, titled "Registration", will include the recognized algorithm name. Additionally, it includes a table, which will list each of the supported operations as rows, identified by the Operation column. The contents of the Parameters column for a given row will contain the IDL type to use for algorithm normalization for that operation, and the contents of the Result column for that row indicate the IDL type that results from performing the supported operation.

If a conforming User Agent implements an algorithm, it MUST implement all of the supported operations and MUST return the IDL type specified.

Additionally, upon initialization, conforming User Agents must perform the define an algorithm steps for each of the supported operations, registering their IDL parameter type as indicated.

18.4. Algorithm Normalization

18.4.1. Description

This section is non-normative.

The AlgorithmIdentifier typedef permits algorithms to either be specified as a DOMString or an object. The usage of DOMString is to permit authors a short-hand for noting algorithms that have no parameters (e.g. SHA-1). The usage of object is to allow an Algorithm (or appropriate subclass) to be specified, which contains all of the associated parameters for an object.

Because of this, it's necessary to define the algorithm for converting an AlgorithmIdentifier into an appropriate dictionary that is usable with this API. This algorithm must be extensible, so as to allow new cryptographic algorithms to be added, and consistent, so that Web IDL type mapping can occur before any control is returned to the calling script, which would potentially allow the mutation of parameters or the script environment.

18.4.2. Internal State Objects

This specification makes use of an internal object, [[supportedAlgorithms]]. This internal object is not exposed to applications.

Because this value is not exposed to applications, the exact type is not specified. It is only required to behave as an associative container of key/value pairs, where comparisons of keys are performed in a case-sensitive manner.

The initial contents of this internal object are as follows:

For each value, v in the List of supported operations, set the v key of the internal object [[supportedAlgorithms]] to a new associative container.

18.4.3. Defining an Algorithm

The define an algorithm algorithm is used by specification authors to indicate how a user agent should normalize arguments for a particular algorithm. Its input is an algorithm name alg, represented as a DOMString, operation name op, represented as a DOMString, and desired IDL dictionary type type. The algorithm behaves as follows:

Let registeredAlgorithms be the associative container stored at the op key of [[supportedAlgorithms]]..
Set the alg key of registeredAlgorithms to the IDL dictionary type type.

18.4.4. Normalizing an algorithm

The normalize an algorithm algorithm defines a process for coercing inputs to a targeted IDL dictionary type, after Web IDL conversion has occurred. It is designed to be extensible, to allow future specifications to define additional algorithms, as well as safe for use with Promises. Its input is an operation name op and an AlgorithmIdentifier alg. Its output is either an IDL dictionary type or an error. It behaves as follows:

If alg is an instance of a DOMString:

Return the result of running the normalize an algorithm algorithm, with the alg set to a new Algorithm dictionary whose name attribute is alg, and with the op set to op.

If alg is an object:

Let registeredAlgorithms be the associative container stored at the op key of [[supportedAlgorithms]].
Let initialAlg be the result of converting the ECMAScript object represented by alg to the IDL dictionary type Algorithm, as defined by [WebIDL].
If an error occurred, return the error and terminate this algorithm.
Let algName be the value of the name attribute of initialAlg.
If registeredAlgorithms contains a key that is a case-insensitive string match for algName:
1. Set algName to the value of the matching key.
2. Let desiredType be the IDL dictionary type stored at algName in registeredAlgorithms.
Otherwise:

Return a new NotSupportedError and terminate this algorithm.
Let normalizedAlgorithm be the result of converting the ECMAScript object represented by alg to the IDL dictionary type desiredType, as defined by [WebIDL].
Set the name attribute of normalizedAlgorithm to algName.
If an error occurred, return the error and terminate this algorithm.
Let dictionaries be a list consisting of the IDL dictionary type desiredType and all of desiredType's inherited dictionaries, in order from least to most derived.
For each dictionary dictionary in dictionaries:
1. For each dictionary member member declared on dictionary, in order:
  1. Let key be the identifier of member.
  2. Let idlValue be the value of the dictionary member with key name of key on normalizedAlgorithm.
  3. If member is of the type BufferSource and is present:
    
    Set the dictionary member on normalizedAlgorithm with key name key to the result of getting a copy of the bytes held by idlValue, replacing the current value.
    
    If member is of the type HashAlgorithmIdentifier:
    
    Set the dictionary member on normalizedAlgorithm with key name key to the result of normalizing an algorithm, with the alg set to idlValue and the op set to "digest".
    
    If member is of the type AlgorithmIdentifier:
    
    Set the dictionary member on normalizedAlgorithm with key name key to the result of normalizing an algorithm, with the alg set to idlValue and the op set to the operation defined by the specification that defines the algorithm identified by algName.
  4. If an error occurred, return the error and terminate this algorithm.
Return normalizedAlgorithm.

18.5. Recommendations

This section is non-normative.

18.5.1. For Authors

As this API is meant to be extensible, in order to keep up with future developments within cryptography, there are no algorithms that conforming user agents are required to implement. As such, authors should check to see what algorithms are currently recommended and supported by implementations.

As highlighted in the Security Considerations, even cryptographic algorithms that might be considered strong for one purpose may be insufficient when used with another purpose. Authors should therefore proceed with extreme caution before inventing new cryptographic protocols.

Additionally, this specification includes several algorithms which, in their default usage, can result in cryptographic vulnerabilities. While these concerns may be mitigated, such as through the combination and composition with additional algorithms provided by this specification, authors should proceed with caution and review the relevant cryptographic literature before using a given algorithm. The inclusion of algorithms within this specification is not an indicator of their suitability for any or all purpose, and instead merely serve to provide as a specification for how a conforming User Agent must implement the given algorithm, if it choses to implement the algorithm.

18.5.2. For Implementers

In order to promote interoperability for developers, this specification includes a list of suggested algorithms. These are considered to be the most widely used algorithms in practice at the time of writing, and therefore provide a good starting point for initial implementations of this specification. The suggested algorithms are:

HMAC using SHA-1
HMAC using SHA-256
RSASSA-PKCS1-v1_5 using SHA-1
RSA-PSS using SHA-256 and MGF1 with SHA-256.
RSA-OAEP using SHA-256 and MGF1 with SHA-256.
ECDSA using P-256 curve and SHA-256
AES-CBC

19. Algorithm Overview

The following section is non-normative.

The table below contains an overview of the algorithms described within this specification, as well as the set of SubtleCrypto methods the algorithm may be used with. In order for an algorithm to be used with a method the corresponding operation or operations, as defined in the procedures for the method, must be defined in the algorithm specification. Note that this mapping of methods to underlying operations is not one-to-one:

The encrypt method requires the encrypt operation.
The decrypt method requires the decrypt operation.
The sign method requires the sign operation.
The verify method requires the verify operation.
The generateKey method requires the generateKey operation.
The importKey method requires the importKey operation.
The exportKey method requires the exportKey operation.
The deriveKey method requires the deriveBits operation for the key derivation algorithm and the get key length and importKey operations for the derived key algorithm.
The deriveBits method requires the deriveBits operation for the key derivation algorithm.
The digest method requires the digest operation.
The wrapKey method requires either the encrypt or wrapKey operation for the wrapping algorithm and the exportKey operation for the wrapped key algorithm.
The unwrapKey method requires either the decrypt or unwrapKey operation for the unwrapping algorithm and the importKey operation for the unwrapped key algorithm.

Application developers and script authors should not interpret this table as a recommendation for the use of particular algorithms. Instead, it simply documents what methods are supported. Authors should refer to the Security considerations for authors section of this document to better understand the risks and concerns that may arise when using certain algorithms.

Algorithm name	encrypt	decrypt	sign	verify	digest	generateKey	deriveKey	deriveBits	importKey	exportKey	wrapKey	unwrapKey
RSASSA-PKCS1-v1_5			✔	✔		✔			✔	✔
RSA-PSS			✔	✔		✔			✔	✔
RSA-OAEP	✔	✔				✔			✔	✔	✔	✔
ECDSA			✔	✔		✔			✔	✔
ECDH						✔	✔	✔	✔	✔
AES-CTR	✔	✔				✔			✔	✔	✔	✔
AES-CBC	✔	✔				✔			✔	✔	✔	✔
AES-GCM	✔	✔				✔			✔	✔	✔	✔
AES-KW						✔			✔	✔	✔	✔
HMAC			✔	✔		✔			✔	✔
SHA-1					✔
SHA-256					✔
SHA-384					✔
SHA-512					✔
HKDF							✔	✔	✔
PBKDF2							✔	✔	✔

20. RSASSA-PKCS1-v1_5

20.1. Description

This section is non-normative.

The "RSASSA-PKCS1-v1_5" algorithm identifier is used to perform signing and verification using the RSASSA-PKCS1-v1_5 algorithm specified in [RFC3447] and using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with RSASSA-PKCS1-v1_5. Such specifications must define the digest operations for the additional hash algorithms and key import steps and key export steps for RSASSA-PKCS1-v1_5.

20.2. Registration

The recognized algorithm name for this algorithm is "RSASSA-PKCS1-v1_5".

Operation	Parameters	Result
sign	None	ArrayBuffer
verify	None	boolean
generateKey	RsaHashedKeyGenParams	CryptoKeyPair
importKey	RsaHashedImportParams	CryptoKey
exportKey	None	object

20.3. RsaKeyGenParams dictionary

IDL


dictionary RsaKeyGenParams : Algorithm {
  // The length, in bits, of the RSA modulus
  [EnforceRange] required unsigned long modulusLength;
  // The RSA public exponent
  required BigInteger publicExponent;
};

20.4. RsaHashedKeyGenParams dictionary

IDL


dictionary RsaHashedKeyGenParams : RsaKeyGenParams {
  // The hash algorithm to use 
  required HashAlgorithmIdentifier hash;
};

20.5. RsaKeyAlgorithm dictionary

IDL


dictionary RsaKeyAlgorithm : KeyAlgorithm {
  // The length, in bits, of the RSA modulus
  required unsigned long modulusLength;
  // The RSA public exponent
  required BigInteger publicExponent;
};

20.6. RsaHashedKeyAlgorithm dictionary

IDL


dictionary RsaHashedKeyAlgorithm : RsaKeyAlgorithm {
  // The hash algorithm that is used with this key
  required KeyAlgorithm hash;
};

20.7. RsaHashedImportParams dictionary

IDL


dictionary RsaHashedImportParams : Algorithm {
  // The hash algorithm to use
  required HashAlgorithmIdentifier hash;
};

20.8. Operations

Sign

If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
Perform the signature generation operation defined in Section 8.2 of [RFC3447] with the key represented by the [[handle]] internal slot of key as the signer's private key and the contents of message as M and using the hash function specified in the hash attribute of the [[algorithm]] internal slot of key as the Hash option for the EMSA-PKCS1-v1_5 encoding method.
If performing the operation results in an error, then throw an OperationError.
Let signature be the value S that results from performing the operation.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing the bytes of signature.

Verify

If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
Perform the signature verification operation defined in Section 8.2 of [RFC3447] with the key represented by the [[handle]] internal slot of key as the signer's RSA public key and the contents of message as M and the contents of signature as S and using the hash function specified in the hash attribute of the [[algorithm]] internal slot of key as the Hash option for the EMSA-PKCS1-v1_5 encoding method.
Let result be a boolean with value true if the result of the operation was "valid signature" and the value false otherwise.
Return result.

Generate Key

If usages contains an entry which is not "sign" or "verify", then throw a SyntaxError.
Generate an RSA key pair, as defined in [RFC3447], with RSA modulus length equal to the modulusLength attribute of normalizedAlgorithm and RSA public exponent equal to the publicExponent attribute of normalizedAlgorithm.
If generation of the key pair fails, then throw an OperationError.
Let algorithm be a new RsaHashedKeyAlgorithm dictionary.
Set the name attribute of algorithm to "RSASSA-PKCS1-v1_5".
Set the modulusLength attribute of algorithm to equal the modulusLength attribute of normalizedAlgorithm.
Set the publicExponent attribute of algorithm to equal the publicExponent attribute of normalizedAlgorithm.
Set the hash attribute of algorithm to equal the hash member of normalizedAlgorithm.
Let publicKey be a new CryptoKey object, associated with the relevant global object of this [HTML], and representing the public key of the generated key pair.
Set the [[type]] internal slot of publicKey to "public"
Set the [[algorithm]] internal slot of publicKey to algorithm.
Set the [[extractable]] internal slot of publicKey to true.
Set the [[usages]] internal slot of publicKey to be the usage intersection of usages and [ "verify" ].
Let privateKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the private key of the generated key pair.
Set the [[type]] internal slot of privateKey to "private"
Set the [[algorithm]] internal slot of privateKey to algorithm.
Set the [[extractable]] internal slot of privateKey to extractable.
Set the [[usages]] internal slot of privateKey to be the usage intersection of usages and [ "sign" ].
Let result be a new CryptoKeyPair dictionary.
Set the publicKey attribute of result to be publicKey.
Set the privateKey attribute of result to be privateKey.
Return result.

Import Key

Let keyData be the key data to be imported.
If format is "spki":
1. If usages contains an entry which is not "verify", then throw a SyntaxError.
2. Let spki be the result of running the parse a subjectPublicKeyInfo algorithm over keyData.
3. If an error occurred while parsing, then throw a DataError.
4. Let hash be undefined.
5. Let alg be the algorithm object identifier field of the algorithm AlgorithmIdentifier field of spki.
6. If alg is equivalent to the rsaEncryption OID defined in Section 2.3.1 of RFC 3279:
  
  Let hash be undefined.
  
  If alg is equivalent to the sha1WithRSAEncryption OID defined in Section A.2.4 of RFC 3279:
  
  Let hash be the string "SHA-1".
  
  If alg is equivalent to the sha256WithRSAEncryption OID defined in Section A.2.4 of RFC 3447:
  
  Let hash be the string "SHA-256".
  
  If alg is equivalent to the sha384WithRSAEncryption OID defined in Section A.2.4 of RFC 3447:
  
  Let hash be the string "SHA-384".
  
  If alg is equivalent to the sha512WithRSAEncryption OID defined in Section A.2.4 of RFC 3447:
  
  Let hash be the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, spki and obtaining hash.
  
  If an error occurred or there are no applicable specifications, throw a DataError.
7. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
8. Let publicKey be the result of performing the parse an ASN.1 structure algorithm, with data as the subjectPublicKeyInfo field of spki, structure as the RSAPublicKey structure specified in Section A.1.1 of RFC 3447, and exactData set to true.
9. If an error occurred while parsing, or it can be determined that publicKey is not a valid public key according to RFC 3447, then throw a DataError.
10. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the RSA public key identified by publicKey.
11. Set the [[type]] internal slot of key to "public"
If format is "pkcs8":
1. If usages contains an entry which is not "sign" then throw a SyntaxError.
2. Let privateKeyInfo be the result of running the parse a privateKeyInfo algorithm over keyData.
3. If an error occurred while parsing, then throw a DataError.
4. Let hash be undefined.
5. Let alg be the algorithm object identifier field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
6. If alg is equivalent to the rsaEncryption OID defined in Section 2.3.1 of RFC 3279:
  
  Let hash be undefined.
  
  If alg is equivalent to the sha1WithRSAEncryption OID defined in Section A.2.4 of RFC 3279:
  
  Let hash be the string "SHA-1".
  
  If alg is equivalent to the sha256WithRSAEncryption OID defined in Section A.2.4 of RFC 3447:
  
  Let hash be the string "SHA-256".
  
  If alg is equivalent to the sha384WithRSAEncryption OID defined in Section A.2.4 of RFC 3447:
  
  Let hash be the string "SHA-384".
  
  If alg is equivalent to the sha512WithRSAEncryption OID defined in Section A.2.4 of RFC 3447:
  
  Let hash be the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, privateKeyInfo and obtaining hash.
  
  If an error occurred or there are no applicable specifications, throw a DataError.
7. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
8. Let rsaPrivateKey be the result of performing the parse an ASN.1 structure algorithm, with data as the privateKey field of privateKeyInfo, structure as the RSAPrivateKey structure specified in Section A.1.2 of RFC 3447, and exactData set to true.
9. If an error occurred while parsing, or if rsaPrivateKey is not a valid RSA private key according to RFC 3447, then throw a DataError.
10. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the RSA private key identified by rsaPrivateKey.
11. Set the [[type]] internal slot of key to "private"
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "d" field of jwk is present and usages contains an entry which is not "sign", or, if the "d" field of jwk is not present and usages contains an entry which is not "verify" then throw a SyntaxError.
3. If the "kty" field of jwk is not a case-sensitive string match to "RSA", then throw a DataError.
4. If usages is non-empty and the "use" field of jwk is present and is not a case-sensitive string match to "sig", then throw a DataError.
5. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
6. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
7. Let hash be a be a string whose initial value is undefined.
8. If the "alg" field of jwk is not present:
  
  Let hash be undefined.
  
  If the "alg" field is equal to the string "RS1":
  
  Let hash be the string "SHA-1".
  
  If the "alg" field is equal to the string "RS256":
  
  Let hash be the string "SHA-256".
  
  If the "alg" field is equal to the string "RS384":
  
  Let hash be the string "SHA-384".
  
  If the "alg" field is equal to the string "RS512":
  
  Let hash be the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, jwk and obtaining hash.
  
  If an error occurred or there are no applicable specifications, throw a DataError.
9. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
10. If the "d" field of jwk is present:
  
  If jwk does not meet the requirements of Section 6.3.2 of JSON Web Algorithms, then throw a DataError.
  
  Let privateKey represents the RSA private key identified by interpreting jwk according to Section 6.3.2 of JSON Web Algorithms.
  
  If privateKey is not a valid RSA private key according to RFC 3447, then throw a DataError.
  
  Let key be a new CryptoKey object that represents privateKey.
  
  Set the [[type]] internal slot of key to "private"
  
  Otherwise:
  
  If jwk does not meet the requirements of Section 6.3.1 of JSON Web Algorithms, then throw a DataError.
  
  Let publicKey represent the RSA public key identified by interpreting jwk according to Section 6.3.1 of JSON Web Algorithms.
  
  If publicKey can be determined to not be a valid RSA public key according to RFC 3447, then throw a DataError.
  
  Let key be a new CryptoKey representing publicKey.
  
  Set the [[type]] internal slot of key to "public"
Otherwise:

throw a NotSupportedError.
Let algorithm be a new RsaHashedKeyAlgorithm dictionary.
Set the name attribute of algorithm to "RSASSA-PKCS1-v1_5"
Set the modulusLength attribute of algorithm to the length, in bits, of the RSA public modulus.
Set the publicExponent attribute of algorithm to the BigInteger representation of the RSA public exponent.
Set the hash attribute of algorithm to the hash member of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Export Key

Let key be the key to be exported.
If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "spki"
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. Let data be an instance of the subjectPublicKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the algorithm field to an AlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm field to the OID 1.2.840.113549.1.1.1
    
    Set the params field to the ASN.1 type NULL.
  - Set the subjectPublicKey field to the result of DER-encoding an RSAPublicKey ASN.1 type, as defined in RFC 3447, Appendix A.1.1, that represents the RSA public key represented by the [[handle]] internal slot of key
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "pkcs8":
1. If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
2. Let data be the result of encoding a privateKeyInfo structure with the following properties:
  - Set the version field to 0.
  - Set the privateKeyAlgorithm field to a PrivateKeyAlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm field to the OID 1.2.840.113549.1.1.1
    
    Set the params field to the ASN.1 type NULL.
  - Set the privateKey field to the result of DER-encoding an RSAPrivateKey ASN.1 type, as defined in RFC 3447, Appendix A.1.2, that represents the RSA private key represented by the [[handle]] internal slot of key
    
    Note
    RFC 5208 specifies that the encoding of this field should be BER encoded in Section 5 (as a "for example"). However, to avoid requiring WebCrypto implementations support BER-encoding and BER-decoding, only DER encodings are produced or accepted.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
- Let jwk be a new JsonWebKey dictionary.
- Set the kty attribute of jwk to the string "RSA".
- Let hash be the name attribute of the hash attribute of key.
- If hash is "SHA-1":
  
  Set the alg attribute of jwk to the string "RS1".
  
  If hash is "SHA-256":
  
  Set the alg attribute of jwk to the string "RS256".
  
  If hash is "SHA-384":
  
  Set the alg attribute of jwk to the string "RS384".
  
  If hash is "SHA-512":
  
  Set the alg attribute of jwk to the string "RS512".
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format, key and obtaining alg.
  
  If an error occurred or there are no applicable specifications, throw a NotSupportedError.
  
  Set the alg attribute of jwk to alg.
- Set the attributes n and e of jwk according to the corresponding definitions in JSON Web Algorithms, Section 6.3.1.
- If the [[type]] internal slot of key is "private":
  
  Set the attributes named d, p, q, dp, dq, and qi of jwk according to the corresponding definitions in JSON Web Algorithms, Section 6.3.2.
  
  If the underlying RSA private key represented by the [[handle]] internal slot of key is represented by more than two primes, set the attribute named oth of jwk according to the corresponding definition in JSON Web Algorithms, Section 6.3.2.7
- Set the key_ops attribute of jwk to the usages attribute of key.
- Set the ext attribute of jwk to the [[extractable]] internal slot of key.
- Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise

throw a NotSupportedError.
Return result.

21. RSA-PSS

21.1. Description

This section is non-normative.

The "RSA-PSS" algorithm identifier is used to perform signing and verification using the RSASSA-PSS algorithm specified in [RFC3447], using the SHA hash functions defined in this specification and the mask generation formula MGF1.

Other specifications may specify the use of additional hash algorithms with RSASSA-PSS. Such specifications must define the digest operation for the additional hash algorithms and key import steps and key export steps for RSASSA-PSS.

21.2. Registration

The recognized algorithm name for this algorithm is "RSA-PSS".

Operation	Parameters	Result
sign	RsaPssParams	ArrayBuffer
verify	RsaPssParams	boolean
generateKey	RsaHashedKeyGenParams	CryptoKeyPair
importKey	RsaHashedImportParams	CryptoKey
exportKey	None	object

21.3. RsaPssParams dictionary

IDL


dictionary RsaPssParams : Algorithm {
  // The desired length of the random salt
  [EnforceRange] required unsigned long saltLength;
};

21.4. Operations

Sign

If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
Perform the signature generation operation defined in Section 8.1 of [RFC3447] with the key represented by the [[handle]] internal slot of key as the signer's private key, K, and the contents of message as the message to be signed, M, and using the hash function specified by the hash attribute of the [[algorithm]] internal slot of key as the Hash option, MGF1 (defined in Section B.2.1 of [RFC3447]) as the MGF option and the saltLength member of normalizedAlgorithm as the salt length option for the EMM-PSS-ENCODE operation.
If performing the operation results in an error, then throw an OperationError.
Let signature be the signature, S, that results from performing the operation.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing the bytes of signature.

Verify

If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
Perform the signature verification operation defined in Section 8.1 of [RFC3447] with the key represented by the [[handle]] internal slot of key as the signer's RSA public key and the contents of message as M and the contents of signature as S and using the hash function specified by the hash attribute of the [[algorithm]] internal slot of key as the Hash option, MGF1 (defined in Section B.2.1 of [RFC3447]) as the MGF option and the saltLength member of normalizedAlgorithm as the salt length option for the EMSA-PSS-VERIFY operation.
Let result be a boolean with the value true if the result of the operation was "valid signature" and the value false otherwise.

Generate Key

If usages contains an entry which is not "sign" or "verify", then throw a SyntaxError.
Generate an RSA key pair, as defined in [RFC3447], with RSA modulus length equal to the modulusLength member of normalizedAlgorithm and RSA public exponent equal to the publicExponent member of normalizedAlgorithm.
If performing the operation results in an error, then throw an OperationError.
Let algorithm be a new RsaHashedKeyAlgorithm dictionary.
Set the name attribute of algorithm to "RSA-PSS".
Set the modulusLength attribute of algorithm to equal the modulusLength member of normalizedAlgorithm.
Set the publicExponent attribute of algorithm to equal the publicExponent member of normalizedAlgorithm.
Set the hash attribute of algorithm to equal the hash member of normalizedAlgorithm.
Let publicKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the public key of the generated key pair.
Set the [[type]] internal slot of publicKey to "public"
Set the [[algorithm]] internal slot of publicKey to algorithm.
Set the [[extractable]] internal slot of publicKey to true.
Set the [[usages]] internal slot of publicKey to be the usage intersection of usages and [ "verify" ].
Let privateKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the private key of the generated key pair.
Set the [[type]] internal slot of privateKey to "private"
Set the [[algorithm]] internal slot of privateKey to algorithm.
Set the [[extractable]] internal slot of privateKey to extractable.
Set the [[usages]] internal slot of privateKey to be the usage intersection of usages and [ "sign" ].
Let result be a new CryptoKeyPair dictionary.
Set the publicKey attribute of result to publicKey.
Set the privateKey attribute of result to privateKey.
Return the result of converting result to an ECMAScript Object, as defined by [WebIDL].

Import Key

Let keyData be the key data to be imported.
If format is "spki":
1. If usages contains an entry which is not "verify" then throw a SyntaxError.
2. Let spki be the result of running the parse a subjectPublicKeyInfo algorithm over keyData.
3. If an error occurred while parsing, then throw a DataError.
4. Let hash be undefined.
5. Let alg be the algorithm object identifier field of the algorithm AlgorithmIdentifier field of spki.
6. If alg is equivalent to the rsaEncryption OID defined in RFC 3447:
  
  Let hash be undefined.
  
  If alg is equivalent to the id-RSASSA-PSS OID defined in RFC 3447:
  
  Let params be the ASN.1 structure contained within the parameters field of the algorithm AlgorithmIdentifier field of spki.
  
  If params is not defined, or is not an instance of the RSASSA-PSS-params ASN.1 type defined in RFC3447, throw a DataError.
  
  Let hashAlg be the AlgorithmIdentifier ASN.1 type within the hashAlgorithm field of params.
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha1 OID defined in RFC 3447:
  
  Set hash to the string "SHA-1".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha256 OID defined in RFC 3447:
  
  Set hash to the string "SHA-256".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha384 OID defined in RFC 3447:
  
  Set hash to the string "SHA-384".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha512 OID defined in RFC 3447:
  
  Set hash to the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, spki and obtaining hash.
  
  If an error occurred or there are no applicable specifications, throw a DataError.
  
  If the algorithm object identifier field of the maskGenAlgorithm field of params is not equivalent to the OID id-mgf1 defined in RFC 3447, throw a NotSupportedError.
  
  If the parameters field of the maskGenAlgorithm field of params is not an instance of the HashAlgorithm ASN.1 type that is identical in content to the hashAlglorithm field of params, throw a NotSupportedError.
  
  Otherwise:
  
  throw a DataError.
7. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
8. Let publicKey be the result of performing the parse an ASN.1 structure algorithm, with data as the subjectPublicKeyInfo field of spki, structure as the RSAPublicKey structure specified in Section A.1.1 of RFC 3447, and exactData set to true.
9. If an error occurred while parsing, or it can be determined that publicKey is not a valid public key according to RFC 3447, then throw a DataError.
10. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the RSA public key identified by publicKey.
11. Set the [[type]] internal slot of key to "public"
If format is "pkcs8":
1. If usages contains an entry which is not "sign" then throw a SyntaxError.
2. Let privateKeyInfo be the result of running the parse a privateKeyInfo algorithm over keyData.
3. If an error occurred while parsing, then throw a DataError.
4. Let hash be undefined.
5. Let alg be the algorithm object identifier field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
6. If alg is equivalent to the rsaEncryption OID defined in RFC 3447:
  
  Let hash be undefined.
  
  If alg is equivalent to the id-RSASSA-PSS OID defined in RFC 3447:
  
  Let params be the ASN.1 structure contained within the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
  
  If params is not defined, or is not an instance of the RSASSA-PSS-params ASN.1 type defined in RFC3447, throw a NotSupportedError.
  
  Let hashAlg be the AlgorithmIdentifier ASN.1 type within the hashAlgorithm field of params.
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha1 OID defined in RFC 3447:
  
  Set hash to the string "SHA-1".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha256 OID defined in RFC 3447:
  
  Set hash to the string "SHA-256".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha384 OID defined in RFC 3447:
  
  Set hash to the string "SHA-384".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha512 OID defined in RFC 3447:
  
  Set hash to the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, privateKeyInfo and obtaining hash.
  
  If an error occurred or there are no applicable specifications, throw a DataError.
  
  If the algorithm object identifier field of the maskGenAlgorithm field of params is not equivalent to the OID id-mgf1 defined in RFC 3447, throw a NotSupportedError.
  
  If the parameters field of the maskGenAlgorithm field of params is not an instance of the HashAlgorithm ASN.1 type that is identical in content to the hashAlglorithm field of params, throw a NotSupportedError.
  
  Otherwise:
  
  throw a DataError.
7. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
8. Let rsaPrivateKey be the result of performing the parse an ASN.1 structure algorithm, with data as the privateKey field of privateKeyInfo, structure as the RSAPrivateKey structure specified in Section A.1.2 of RFC 3447, and exactData set to true.
9. If an error occurred while parsing, or if rsaPrivateKey is not a valid RSA private key according to RFC 3447, then throw a DataError.
10. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the RSA private key identified by rsaPrivateKey.
11. Set the [[type]] internal slot of key to "private"
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "d" field of jwk is present and usages contains an entry which is not "sign", or, if the "d" field of jwk is not present and usages contains an entry which is not "verify" then throw a SyntaxError.
3. If the "kty" field of jwk is not a case-sensitive string match to "RSA", then throw a DataError.
4. If usages is non-empty and the "use" field of jwk is present and is not a case-sensitive string match to "sig", then throw a DataError.
5. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
6. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
7. If the "alg" field of jwk is not present:
  
  Let hash be undefined.
  
  If the "alg" field is equal to the string "PS1":
  
  Let hash be the string "SHA-1".
  
  If the "alg" field is equal to the string "PS256":
  
  Let hash be the string "SHA-256".
  
  If the "alg" field is equal to the string "PS384":
  
  Let hash be the string "SHA-384".
  
  If the "alg" field is equal to the string "PS512":
  
  Let hash be the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, jwk and obtaining hash.
  
  If an error occurred or there are no applicable specifications, throw a DataError.
8. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
9. If the "d" field of jwk is present:
  
  If jwk does not meet the requirements of Section 6.3.2 of JSON Web Algorithms, then throw a DataError.
  
  Let privateKey represent the RSA public key identified by interpreting jwk according to Section 6.3.1 of JSON Web Algorithms.
  
  If privateKey can be determined to not be a valid RSA public key according to RFC 3447, then throw a DataError.
  
  Let key be a new CryptoKey representing privateKey.
  
  Set the [[type]] internal slot of key to "private"
  
  Otherwise:
  
  If jwk does not meet the requirements of Section 6.3.1 of JSON Web Algorithms, then throw a DataError.
  
  Let publicKey represent the RSA public key identified by interpreting jwk according to Section 6.3.1 of JSON Web Algorithms.
  
  If publicKey can be determined to not be a valid RSA public key according to RFC 3447, then throw a DataError.
  
  Let key be a new CryptoKey representing publicKey.
  
  Set the [[type]] internal slot of key to "public"
Otherwise:

throw a NotSupportedError.
Let algorithm be a new RsaHashedKeyAlgorithm dictionary.
Set the name attribute of algorithm to "RSA-PSS"
Set the modulusLength attribute of algorithm to the length, in bits, of the RSA public modulus.
Set the publicExponent attribute of algorithm to the BigInteger representation of the RSA public exponent.
Set the hash attribute of algorithm to the hash member of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm
Return key.

Export Key

Let key be the key to be exported.
If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "spki"
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. Let data be an instance of the subjectPublicKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the algorithm field to an AlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-RSASSA-PSS defined in RFC 3447.
    
    Set the params field to an instance of the RSASSA-PSS-params ASN.1 type with the following properties:
    
    Set the hashAlgorithm field to an instance of the HashAlgorithm ASN.1 type with the following properties:
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-1":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha1 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-256":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha256 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-384":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha384 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-512":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha512 defined in RFC 3447.
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the hash attribute of the [[algorithm]] internal slot of key and obtaining hashOid and hashParams.
    
    Set the algorithm object identifier of hashAlgorithm to hashOid.
    
    Set the params field of hashAlgorithm to hashParams if hashParams is not undefined and omit the params field otherwise.
    
    Set the maskGenAlgorithm field to an instance of the MaskGenAlgorithm ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-mgf1 defined in RFC 3447.
    
    Set the params field to an instance of the HashAlgorithm ASN.1 type that is identical to the hashAlgorithm field.
    
    Set the saltLength field to the length in octets of the digest algorithm identified by the name attribute of the hash attribute of the [[algorithm]] internal slot of key.
  - Set the subjectPublicKey field to the result of DER-encoding an RSAPublicKey ASN.1 type, as defined in RFC 3447, Appendix A.1.1, that represents the RSA public key represented by the [[handle]] internal slot of key
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "pkcs8":
1. If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
2. Let data be the result of encoding a privateKeyInfo structure with the following properties:
  - Set the version field to 0.
  - Set the privateKeyAlgorithm field to an PrivateKeyAlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-RSASSA-PSS defined in RFC 3447.
    
    Set the params field to an instance of the RSASSA-PSS-params ASN.1 type with the following properties:
    
    Set the hashAlgorithm field to an instance of the HashAlgorithm ASN.1 type with the following properties:
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-1":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha1 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-256":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha256 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-384":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha384 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-512":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha512 defined in RFC 3447.
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the hash attribute of the [[algorithm]] internal slot of key and obtaining hashOid and hashParams.
    
    Set the algorithm object identifier of hashAlgorithm to hashOid.
    
    Set the params field of hashAlgorithm to hashParams if hashParams is not undefined and omit the params field otherwise.
    
    Set the maskGenAlgorithm field to an instance of the MaskGenAlgorithm ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-mgf1 defined in RFC 3447.
    
    Set the params field to an instance of the HashAlgorithm ASN.1 type that is identical to the hashAlgorithm field.
    
    Set the saltLength field to the length in octets of the digest algorithm identified by the name attribute of the hash attribute of the [[algorithm]] internal slot of key.
  - Set the privateKey field to the result of DER-encoding an RSAPrivateKey ASN.1 type, as defined in RFC 3447, Appendix A.1.2, that represents the RSA private key represented by the [[handle]] internal slot of key
    
    Note
    RFC 5208 specifies that the encoding of this field should be BER encoded in Section 5 (as a "for example"). However, to avoid requiring WebCrypto implementations support BER-encoding and BER-decoding, only DER encodings are produced or accepted.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
- Let jwk be a new JsonWebKey dictionary.
- Set the kty attribute of jwk to the string "RSA".
- Let hash be the name attribute of the hash attribute of the [[algorithm]] internal slot of key.
- If hash is "SHA-1":
  
  Set the alg attribute of jwk to the string "PS1".
  
  If hash is "SHA-256":
  
  Set the alg attribute of jwk to the string "PS256".
  
  If hash is "SHA-384":
  
  Set the alg attribute of jwk to the string "PS384".
  
  If hash is "SHA-512":
  
  Set the alg attribute of jwk to the string "PS512".
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format and the hash attribute of the [[algorithm]] internal slot of key and obtaining alg.
  
  Set the alg attribute of jwk to alg.
- Set the attributes n and e of jwk according to the corresponding definitions in JSON Web Algorithms, Section 6.3.1.
- If the [[type]] internal slot of key is "private":
  
  Set the attributes named d, p, q, dp, dq, and qi of jwk according to the corresponding definitions in JSON Web Algorithms, Section 6.3.2.
  
  If the underlying RSA private key represented by the [[handle]] internal slot of key is represented by more than two primes, set the attribute named oth of jwk according to the corresponding definition in JSON Web Algorithms, Section 6.3.2.7
- Set the key_ops attribute of jwk to the usages attribute of key.
- Set the ext attribute of jwk to the [[extractable]] internal slot of key.
- Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise

throw a NotSupportedError.
Return result.

22. RSA-OAEP

22.1. Description

This section is non-normative.

The "RSA-OAEP" algorithm identifier is used to perform encryption and decryption ordering to the RSAES-OAEP algorithm specified in [RFC3447], using the SHA hash functions defined in this specification and using the mask generation function MGF1.

Other specifications may specify the use of additional hash algorithms with RSAES-OAEP. Such specifications must define the digest operation for the additional hash algorithm and key import steps and key export steps for RSAES-OAEP.

22.2. Registration

The recognized algorithm name for this algorithm is "RSA-OAEP".

Operation	Parameters	Result
encrypt	RsaOaepParams	ArrayBuffer
decrypt	RsaOaepParams	ArrayBuffer
generateKey	RsaHashedKeyGenParams	CryptoKeyPair
importKey	RsaHashedImportParams	CryptoKey
exportKey	None	object

22.3. RsaOaepParams dictionary

IDL


dictionary RsaOaepParams : Algorithm {
  // The optional label/application data to associate with the message
  BufferSource label;
};

22.4. Operations

Encrypt

If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
Let label be the contents of the label member of normalizedAlgorithm or the empty octet string if the label member of normalizedAlgorithm is not present.
Perform the encryption operation defined in Section 7.1 of [RFC3447] with the key represented by key as the recipient's RSA public key, the contents of plaintext as the message to be encrypted, M and label as the label, L, and with the hash function specified by the hash attribute of the [[algorithm]] internal slot of key as the Hash option and MGF1 (defined in Section B.2.1 of [RFC3447]) as the MGF option.
If performing the operation results in an error, then throw an OperationError.
Let ciphertext be the value C that results from performing the operation.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing ciphertext.

Decrypt

If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
Let label be the contents of the label member of normalizedAlgorithm or the empty octet string if the label member of normalizedAlgorithm is not present.
Perform the decryption operation defined in Section 7.1 of [RFC3447] with the key represented by key as the recipient's RSA private key, the contents of ciphertext as the ciphertext to be decrypted, C, and label as the label, L, and with the hash function specified by the hash attribute of the [[algorithm]] internal slot of key as the Hash option and MGF1 (defined in Section B.2.1 of [RFC3447]) as the MGF option.
If performing the operation results in an error, then throw an OperationError.
Let plaintext the value M that results from performing the operation.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing plaintext.

Generate Key

If usages contains an entry which is not "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
Generate an RSA key pair, as defined in [RFC3447], with RSA modulus length equal to the modulusLength member of normalizedAlgorithm and RSA public exponent equal to the publicExponent member of normalizedAlgorithm.
If performing the operation results in an error, then throw an OperationError.
Let algorithm be a new RsaHashedKeyAlgorithm object.
Set the name attribute of algorithm to "RSA-OAEP".
Set the modulusLength attribute of algorithm to equal the modulusLength member of normalizedAlgorithm.
Set the publicExponent attribute of algorithm to equal the publicExponent member of normalizedAlgorithm.
Set the hash attribute of algorithm to equal the hash member of normalizedAlgorithm.
Let publicKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the public key of the generated key pair.
Set the [[type]] internal slot of publicKey to "public"
Set the [[algorithm]] internal slot of publicKey to algorithm.
Set the [[extractable]] internal slot of publicKey to true.
Set the [[usages]] internal slot of publicKey to be the usage intersection of usages and [ "encrypt", "wrapKey" ].
Let privateKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the private key of the generated key pair.
Set the [[type]] internal slot of privateKey to "private"
Set the [[algorithm]] internal slot of privateKey to algorithm.
Set the [[extractable]] internal slot of privateKey to extractable.
Set the [[usages]] internal slot of privateKey to be the usage intersection of usages and [ "decrypt", "unwrapKey" ].
Let result be a new CryptoKeyPair dictionary.
Set the publicKey attribute of result to be publicKey.
Set the privateKey attribute of result to be privateKey.
Return the result of converting result to an ECMAScript Object, as defined by [WebIDL].

Import Key

Let keyData be the key data to be imported.
If format is "spki":
1. If usages contains an entry which is not "encrypt" or "wrapKey", then throw a SyntaxError.
2. Let spki be the result of running the parse a subjectPublicKeyInfo algorithm over keyData.
3. If an error occurred while parsing, then throw a DataError.
4. Let hash be a string whose initial value is undefined.
5. Let alg be the algorithm object identifier field of the algorithm AlgorithmIdentifier field of spki.
6. If alg is equivalent to the rsaEncryption OID defined in RFC 3447:
  
  Let hash be undefined.
  
  If alg is equivalent to the id-RSAES-OAEP OID defined in RFC 3447:
  
  Let params be the ASN.1 structure contained within the parameters field of the algorithm AlgorithmIdentifier field of spki.
  
  If params is not defined, or is not an instance of the RSAES-OAEP-params ASN.1 type defined in RFC3447, throw a DataError.
  
  Let hashAlg be the AlgorithmIdentifier ASN.1 type within the hashAlgorithm field of params.
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha1 OID defined in RFC 3447:
  
  Set hash to the string "SHA-1".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha256 OID defined in RFC 3447:
  
  Set hash to the string "SHA-256".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha384 OID defined in RFC 3447:
  
  Set hash to the string "SHA-384".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha512 OID defined in RFC 3447:
  
  Set hash to the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, spki and obtaining hash.
  
  If an error occured or there are no applicable specifications, throw a DataError.
  
  If the algorithm object identifier field of the maskGenAlgorithm field of params is not equivalent to the OID id-mgf1 defined in RFC 3447, throw a NotSupportedError.
  
  If the parameters field of the maskGenAlgorithm field of params is not an instance of the HashAlgorithm ASN.1 type that is identical in content to the hashAlglorithm field of params, throw a NotSupportedError.
  
  Otherwise:
  
  throw a DataError.
7. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
8. Let publicKey be the result of performing the parse an ASN.1 structure algorithm, with data as the subjectPublicKeyInfo field of spki, structure as the RSAPublicKey structure specified in Section A.1.1 of RFC 3447, and exactData set to true.
9. If an error occurred while parsing, or it can be determined that publicKey is not a valid public key according to RFC 3447, then throw a DataError.
10. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the RSA public key identified by publicKey.
11. Set the [[type]] internal slot of key to "public"
If format is "pkcs8":
1. If usages contains an entry which is not "decrypt" or "unwrapKey", then throw a SyntaxError.
2. Let privateKeyInfo be the result of running the parse a privateKeyInfo algorithm over keyData.
3. If an error occurred while parsing, then throw a DataError.
4. Let hash be a string whose initial value is undefined.
5. Let alg be the algorithm object identifier field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
6. If alg is equivalent to the rsaEncryption OID defined in RFC 3447:
  
  Let hash be undefined.
  
  If alg is equivalent to the id-RSAES-OAEP OID defined in RFC 3447:
  
  Let params be the ASN.1 structure contained within the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
  
  If params is not defined, or is not an instance of the RSAES-OAEP-params ASN.1 type defined in RFC3447, throw a NotSupportedError.
  
  Let hashAlg be the AlgorithmIdentifier ASN.1 type within the hashAlgorithm field of params.
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha1 OID defined in RFC 3447:
  
  Set hash to the string "SHA-1".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha256 OID defined in RFC 3447:
  
  Set hash to the string "SHA-256".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha384 OID defined in RFC 3447:
  
  Set hash to the string "SHA-384".
  
  If the algorithm object identifier field of hashAlg is equivalent to the id-sha512 OID defined in RFC 3447:
  
  Set hash to the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, spki and obtaining hash.
  
  If an error occured or there are no applicable specifications, throw a DataError.
  
  If the algorithm object identifier field of the maskGenAlgorithm field of params is not equivalent to the OID id-mgf1 defined in RFC 3447, throw a NotSupportedError.
  
  If the parameters field of the maskGenAlgorithm field of params is not an instance of the HashAlgorithm ASN.1 type that is identical in content to the hashAlglorithm field of params, throw a NotSupportedError.
  
  Otherwise:
  
  throw a DataError.
7. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
8. Let rsaPrivateKey be the result of performing the parse an ASN.1 structure algorithm, with data as the privateKey field of privateKeyInfo, structure as the RSAPrivateKey structure specified in Section A.1.2 of RFC 3447, and exactData set to true.
9. If an error occurred while parsing, or if rsaPrivateKey is not a valid RSA private key according to RFC 3447, then throw a DataError.
10. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the RSA private key identified by rsaPrivateKey.
11. Set the [[type]] internal slot of key to "private"
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "d" field of jwk is present and usages contains an entry which is not "decrypt" or "unwrapKey", then throw a SyntaxError.
3. If the "d" field of jwk is not present and usages contains an entry which is not "encrypt" or "wrapKey", then throw a SyntaxError.
4. If the "kty" field of jwk is not a case-sensitive string match to "RSA", then throw a DataError.
5. If usages is non-empty and the "use" field of jwk is present and is not a case-sensitive string match to "enc", then throw a DataError.
6. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
7. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
8. If the alg field of jwk is not present:
  
  Let hash be undefined.
  
  If the alg field of jwk is equal to "RSA-OAEP":
  
  Let hash be the string "SHA-1".
  
  If the alg field of jwk is equal to "RSA-OAEP-256":
  
  Let hash be the string "SHA-256".
  
  If the alg field of jwk is equal to "RSA-OAEP-384":
  
  Let hash be the string "SHA-384".
  
  If the alg field of jwk is equal to "RSA-OAEP-512":
  
  Let hash be the string "SHA-512".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, jwk and obtaining hash.
  
  If an error occured or there are no applicable specifications, throw a DataError.
9. If hash is not undefined:
  
  Let normalizedHash be the result of normalize an algorithm with alg set to hash and op set to digest.
  
  If normalizedHash is not equal to the hash member of normalizedAlgorithm, throw a DataError.
10. If the "d" field of jwk is present:
  
  If jwk does not meet the requirements of Section 6.3.2 of JSON Web Algorithms, then throw a DataError.
  
  Let privateKey represent the RSA public key identified by interpreting jwk according to Section 6.3.1 of JSON Web Algorithms.
  
  If privateKey can be determined to not be a valid RSA public key according to RFC 3447, then throw a DataError.
  
  Let key be a new CryptoKey representing privateKey.
  
  Set the [[type]] internal slot of key to "private"
  
  Otherwise:
  
  If jwk does not meet the requirements of Section 6.3.1 of JSON Web Algorithms, then throw a DataError.
  
  Let publicKey represent the RSA public key identified by interpreting jwk according to Section 6.3.1 of JSON Web Algorithms.
  
  If publicKey can be determined to not be a valid RSA public key according to RFC 3447, then throw a DataError.
  
  Let key be a new CryptoKey representing publicKey.
  
  Set the [[type]] internal slot of key to "public"
Otherwise:

throw a NotSupportedError.
Let algorithm be a new RsaHashedKeyAlgorithm.
Set the name attribute of algorithm to "RSA-OAEP"
Set the modulusLength attribute of algorithm to the length, in bits, of the RSA public modulus.
Set the publicExponent attribute of algorithm to the BigInteger representation of the RSA public exponent.
Set the hash attribute of algorithm to the hash member of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm
Return key.

Export Key

Let key be the key to be exported.
If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "spki"
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. Let data be an instance of the subjectPublicKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the algorithm field to an AlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-RSAES-OAEP defined in RFC 3447.
    
    Set the params field to an instance of the RSAES-OAEP-params ASN.1 type with the following properties:
    
    Set the hashAlgorithm field to an instance of the HashAlgorithm ASN.1 type with the following properties:
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-1":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha1 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-256":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha256 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-384":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha384 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-512":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha512 defined in RFC 3447.
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the hash attribute of the [[algorithm]] internal slot of key and obtaining hashOid and hashParams.
    
    Set the algorithm object identifier of hashAlgorithm to hashOid.
    
    Set the params field of hashAlgorithm to hashParams if hashParams is not undefined and omit the params field otherwise.
    
    Set the maskGenAlgorithm field to an instance of the MaskGenAlgorithm ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-mgf1 defined in RFC 3447.
    
    Set the params field to an instance of the HashAlgorithm ASN.1 type that is identical to the hashAlgorithm field.
  - Set the subjectPublicKey field to the result of DER-encoding an RSAPublicKey ASN.1 type, as defined in RFC 3447, Appendix A.1.1, that represents the RSA public key represented by the [[handle]] internal slot of key
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "pkcs8":
1. If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
2. Let data be the result of encoding a privateKeyInfo structure with the following properties:
  - Set the version field to 0.
  - Set the privateKeyAlgorithm field to an PrivateKeyAlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-RSAES-OAEP defined in RFC 3447.
    
    Set the params field to an instance of the RSAES-OAEP-params ASN.1 type with the following properties:
    
    Set the hashAlgorithm field to an instance of the HashAlgorithm ASN.1 type with the following properties:
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-1":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha1 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-256":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha256 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-384":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha384 defined in RFC 3447.
    
    If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-512":
    
    Set the algorithm object identifier of hashAlgorithm to the OID id-sha512 defined in RFC 3447.
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the hash attribute of the [[algorithm]] internal slot of key and obtaining hashOid and hashParams.
    
    Set the algorithm object identifier of hashAlgorithm to hashOid.
    
    Set the params field of hashAlgorithm to hashParams if hashParams is not undefined and omit the params field otherwise.
    
    Set the maskGenAlgorithm field to an instance of the MaskGenAlgorithm ASN.1 type with the following properties:
    
    Set the algorithm field to the OID id-mgf1 defined in RFC 3447.
    
    Set the params field to an instance of the HashAlgorithm ASN.1 type that is identical to the hashAlgorithm field.
  - Set the privateKey field to the result of DER-encoding an RSAPrivateKey ASN.1 type, as defined in RFC 3447, Appendix A.1.2, that represents the RSA private key represented by the [[handle]] internal slot of key
    
    Note
    RFC 5208 specifies that the encoding of this field should be BER encoded in Section 5 (as a "for example"). However, to avoid requiring WebCrypto implementations support BER-encoding and BER-decoding, only DER encodings are produced or accepted.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
- Let jwk be a new JsonWebKey dictionary.
- Set the kty attribute of jwk to the string "RSA".
- If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-1":
  
  Set the alg attribute of jwk to the string "RSA-OAEP".
  
  If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-256":
  
  Set the alg attribute of jwk to the string "RSA-OAEP-256".
  
  If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-384":
  
  Set the alg attribute of jwk to the string "RSA-OAEP-384".
  
  If the name attribute of the hash attribute of the [[algorithm]] internal slot of key is "SHA-512":
  
  Set the alg attribute of jwk to the string "RSA-OAEP-512".
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format and the hash attribute of the [[algorithm]] internal slot of key and obtaining alg.
  
  Set the alg attribute of jwk to alg.
- Set the attributes n and e of jwk according to the corresponding definitions in JSON Web Algorithms, Section 6.3.1.
- If the [[type]] internal slot of key is "private":
  
  Set the attributes named d, p, q, dp, dq, and qi of jwk according to the corresponding definitions in JSON Web Algorithms, Section 6.3.2.
  
  If the underlying RSA private key represented by the [[handle]] internal slot of key is represented by more than two primes, set the attribute named oth of jwk according to the corresponding definition in JSON Web Algorithms, Section 6.3.2.7
- Set the key_ops attribute of jwk to the usages attribute of key.
- Set the ext attribute of jwk to the [[extractable]] internal slot of key.
- Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise

throw a NotSupportedError.
Return result.

23. ECDSA

23.1. Description

This section is non-normative.

The "ECDSA" algorithm identifier is used to perform signing and verification using the ECDSA algorithm specified in [RFC6090] and using the SHA hash functions and elliptic curves defined in this specification.

Other specifications may specify the use of additional elliptic curves and hash algorithms with ECDSA. To specify additional hash algorithms to be used with ECDSA, a specification must define a registered algorithm that supports the digest operation. To specify an additional elliptic curve a specification must define the curve name, ECDSA signature steps, ECDSA verification steps, ECDSA generation steps, ECDSA key import steps and ECDSA key export steps.

23.2. Registration

The recognized algorithm name for this algorithm is "ECDSA".

Operation	Parameters	Result
sign	EcdsaParams	ArrayBuffer
verify	EcdsaParams	boolean
generateKey	EcKeyGenParams	CryptoKeyPair
importKey	EcKeyImportParams	CryptoKey
exportKey	None	object

23.3. EcdsaParams dictionary

IDL


dictionary EcdsaParams : Algorithm {
  // The hash algorithm to use
  required HashAlgorithmIdentifier hash;
};

23.4. EcKeyGenParams dictionary

IDL


typedef DOMString NamedCurve;

dictionary EcKeyGenParams : Algorithm {
  // A named curve
  required NamedCurve namedCurve;
};

The NamedCurve type represents named elliptic curves, which are a convenient way to specify the domain parameters of well-known elliptic curves. The following values defined by this specification:

"P-256": NIST recommended curve P-256, also known as secp256r1.
"P-384": NIST recommended curve P-384, also known as secp384r1.
"P-521": NIST recommended curve P-521, also known as secp521r1.

Other specifications may define additional values.

23.5. EcKeyAlgorithm dictionary

IDL


dictionary EcKeyAlgorithm : KeyAlgorithm {
  // The named curve that the key uses
  required NamedCurve namedCurve;
};

23.6. EcKeyImportParams dictionary

IDL


dictionary EcKeyImportParams : Algorithm {
  // A named curve
  required NamedCurve namedCurve;
};

23.7. Operations

Sign

When signing, the following algorithm should be used:

If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
Let hashAlgorithm be the hash member of normalizedAlgorithm.
Let M be the result of performing the digest operation specified by hashAlgorithm using message.
Let d be the ECDSA private key associated with key.
Let params be the EC domain parameters associated with key.
If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
1. Perform the ECDSA signing process, as specified in RFC6090, Section 5.4, with M as the message, using params as the EC domain parameters, and with d as the private key.
2. Let r and s be the pair of integers resulting from performing the ECDSA signing process.
3. Let result be a new empty ArrayBuffer associated with the relevant global object of this [HTML].
4. Let n be the smallest integer such that n * 8 is greater than the logarithm to base 2 of the order of the base point of the elliptic curve identified by params.
5. Convert r to an octet string of length n and append this sequence of bytes to result.
6. Convert s to an octet string of length n and append this sequence of bytes to result.
Otherwise, the namedCurve attribute of the [[algorithm]] internal slot of key is a value specified in an applicable specification:

Perform the ECDSA signature steps specified in that specification, passing in M, params and d and resulting in result.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing the bytes of result.

Verify

When verifying, the following algorithm should be used:

If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
Let hashAlgorithm be the hash member of normalizedAlgorithm.
Let M be the result of performing the digest operation specified by hashAlgorithm using message.
Let Q be the ECDSA public key associated with key.
Let params be the EC domain parameters associated with key.
If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":

Perform the ECDSA verifying process, as specified in RFC6090, Section 5.3, with M as the received message, signature as the received signature and using params as the EC domain parameters, and Q as the public key.

Otherwise, the namedCurve attribute of the [[algorithm]] internal slot of key is a value specified in an applicable specification:

Perform the ECDSA verification steps specified in that specification passing in M, signature, params and Q and resulting in an indication of whether or not the purported signature is valid.
Let result be a boolean with the value true if the signature is valid and the value false otherwise.
Return result.

Generate Key

If usages contains a value which is not one of "sign" or "verify", then throw a SyntaxError.
If the namedCurve member of normalizedAlgorithm is "P-256", "P-384" or "P-521":

Generate an Elliptic Curve key pair, as defined in [RFC6090] with domain parameters for the curve identified by the namedCurve member of normalizedAlgorithm.

If the namedCurve member of normalizedAlgorithm is a value specified in an applicable specification:

Perform the ECDSA key generation steps specified in that specification, passing in normalizedAlgorithm and resulting in an elliptic curve key pair.

Otherwise:

throw a NotSupportedError
If performing the key generation operation results in an error, then throw an OperationError.
Let algorithm be a new EcKeyAlgorithm object.
Set the name attribute of algorithm to "ECDSA".
Set the namedCurve attribute of algorithm to equal the namedCurve member of normalizedAlgorithm.
Let publicKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the public key of the generated key pair.
Set the [[type]] internal slot of publicKey to "public"
Set the [[algorithm]] internal slot of publicKey to algorithm.
Set the [[extractable]] internal slot of publicKey to true.
Set the [[usages]] internal slot of publicKey to be the usage intersection of usages and [ "verify" ].
Let privateKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the private key of the generated key pair.
Set the [[type]] internal slot of privateKey to "private"
Set the [[algorithm]] internal slot of privateKey to algorithm.
Set the [[extractable]] internal slot of privateKey to extractable.
Set the [[usages]] internal slot of privateKey to be the usage intersection of usages and [ "sign" ].
Let result be a new CryptoKeyPair dictionary.
Set the publicKey attribute of result to be publicKey.
Set the privateKey attribute of result to be privateKey.
Return the result of converting result to an ECMAScript Object, as defined by [WebIDL].

Import Key

Let keyData be the key data to be imported.
If format is "spki":
1. If usages contains a value which is not "verify" then throw a SyntaxError.
2. Let spki be the result of running the parse a subjectPublicKeyInfo algorithm over keyData
3. If an error occurred while parsing, then throw a DataError.
4. If the algorithm object identifier field of the algorithm AlgorithmIdentifier field of spki is not equal to the id-ecPublicKey object identifier defined in RFC 5480, then throw a DataError.
5. If the parameters field of the algorithm AlgorithmIdentifier field of spki is absent, then throw a DataError.
6. Let params be the parameters field of the algorithm AlgorithmIdentifier field of spki.
7. If params is not an instance of the ECParameters ASN.1 type defined in RFC 5480 that specifies a namedCurve, then throw a DataError.
8. Let namedCurve be a string whose initial value is undefined.
9. If params is equivalent to the secp256r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-256".
  
  If params is equivalent to the secp384r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-384".
  
  If params is equivalent to the secp521r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-521".
10. If namedCurve is not undefined:
  
  Let publicKey be the Elliptic Curve public key identified by performing the conversion steps defined in Section 2.3.4 of SEC 1 using the the subjectPublicKey field of spki.
  
  The uncompressed point format MUST be supported.
  
  If the implementation does not support the compressed point format and a compressed point is provided, throw a DataError.
  
  If a decode error occurs or an identity point is found, throw a DataError.
  
  Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents publicKey.
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, spki and obtaining namedCurve and key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
11. If namedCurve is defined, and not equal to the namedCurve member of normalizedAlgorithm, throw a DataError.
12. If the public key value is not a valid point on the Elliptic Curve identified by the namedCurve member of normalizedAlgorithm throw a DataError.
13. Set the [[type]] internal slot of key to "public"
14. Let algorithm be a new EcKeyAlgorithm.
15. Set the name attribute of algorithm to "ECDSA".
16. Set the namedCurve attribute of algorithm to namedCurve.
17. Set the [[algorithm]] internal slot of key to algorithm.
If format is "pkcs8":
1. If usages contains a value which is not "sign" then throw a SyntaxError.
2. Let privateKeyInfo be the result of running the parse a privateKeyInfo algorithm over keyData.
3. If an error occurs while parsing, then throw a DataError.
4. If the algorithm object identifier field of the privateKeyAlgorithm PrivateKeyAlgorithm field of privateKeyInfo is not equal to the id-ecPublicKey object identifier defined in RFC 5480, then throw a DataError.
5. If the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo is not present, then throw a DataError.
6. Let params be the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
7. If params is not an instance of the ECParameters ASN.1 type defined in RFC 5480 that specifies a namedCurve, then throw a DataError.
8. Let namedCurve be a string whose initial value is undefined.
9. If params is equivalent to the secp256r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-256".
  
  If params is equivalent to the secp384r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-384".
  
  If params is equivalent to the secp521r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-521".
10. If namedCurve is not undefined:
  
  Let ecPrivateKey be the result of performing the parse an ASN.1 structure algorithm, with data as the privateKey field of privateKeyInfo, structure as the ASN.1 ECPrivateKey structure specified in Section 3 of RFC 5915, and exactData set to true.
  
  If an error occurred while parsing, then throw a DataError.
  
  If the parameters field of ecPrivateKey is present, and is not an instance of the namedCurve ASN.1 type defined in RFC 5480, or does not contain the same object identifier as the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo, then throw a DataError.
  
  Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the Elliptic Curve private key identified by performing the conversion steps defined in Section 3 of RFC 5915 using ecPrivateKey.
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, privateKeyInfo and obtaining namedCurve and key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
11. If namedCurve is defined, and not equal to the namedCurve member of normalizedAlgorithm, throw a DataError.
12. If the private key value is not a valid point on the Elliptic Curve identified by the namedCurve member of normalizedAlgorithm throw a DataError.
13. Set the [[type]] internal slot of key to "private"
14. Let algorithm be a new EcKeyAlgorithm.
15. Set the name attribute of algorithm to "ECDSA".
16. Set the namedCurve attribute of algorithm to namedCurve.
17. Set the [[algorithm]] internal slot of key to algorithm.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "d" field is present and usages contains a value which is not "sign", or, if the "d" field is not present and usages contains a value which is not "verify" then throw a SyntaxError.
3. If the "kty" field of jwk is not "EC", then throw a DataError.
4. If usages is non-empty and the "use" field of jwk is present and is not "sig", then throw a DataError.
5. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key, or it does not contain all of the specified usages values, then throw a DataError.
6. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
7. Let namedCurve be a string whose value is equal to the "crv" field of jwk.
8. If namedCurve is not equal to the namedCurve member of normalizedAlgorithm, throw a DataError.
9. If namedCurve is equal to "P-256", "P-384" or "P-521":
  
  Let algNamedCurve be a string whose initial value is undefined.
  
  If the "alg" field is not present:
  
  Let algNamedCurve be undefined.
  
  If the "alg" field is equal to the string "ES256":
  
  Let algNamedCurve be the string "P-256".
  
  If the "alg" field is equal to the string "ES384":
  
  Let algNamedCurve be the string "P-384".
  
  If the "alg" field is equal to the string "ES512":
  
  Let algNamedCurve be the string "P-521".
  
  otherwise:
  
  throw a DataError.
  
  If algNamedCurve is defined, and is not equal to namedCurve, throw a DataError.
  
  If the "d" field is present:
  
  If jwk does not meet the requirements of Section 6.2.2 of JSON Web Algorithms, then throw a DataError.
  
  Let key be a new CryptoKey object that represents the Elliptic Curve private key identified by interpreting jwk according to Section 6.2.2 of JSON Web Algorithms.
  
  Set the [[type]] internal slot of Key to "private".
  
  Otherwise:
  
  If jwk does not meet the requirements of Section 6.2.1 of JSON Web Algorithms, then throw a DataError.
  
  Let key be a new CryptoKey object that represents the Elliptic Curve public key identified by interpreting jwk according to Section 6.2.1 of JSON Web Algorithms.
  
  Set the [[type]] internal slot of Key to "public".
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, jwk and obtaining key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
10. If the key value is not a valid point on the Elliptic Curve identified by the namedCurve member of normalizedAlgorithm throw a DataError.
11. Let algorithm be a new instance of an EcKeyAlgorithm object.
12. Set the name attribute of algorithm to "ECDSA".
13. Set the namedCurve attribute of algorithm to namedCurve.
14. Set the [[algorithm]] internal slot of key to algorithm.
If format is "raw":
1. If the namedCurve member of normalizedAlgorithm is not a named curve, then throw a DataError.
2. If usages contains a value which is not "verify" then throw a SyntaxError.
3. If namedCurve is "P-256", "P-384" or "P-521":
  
  Let Q be the elliptic curve point on the curve identified by the namedCurve member of normalizedAlgorithm identified by performing the conversion steps defined in Section 2.3.4 of SEC 1 on keyData.
  
  The uncompressed point format MUST be supported.
  
  If the implementation does not support the compressed point format and a compressed point is provided, throw a DataError.
  
  If a decode error occurs or an identity point is found, throw a DataError.
  
  Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents Q
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, keyData and obtaining key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
4. Let algorithm be a new EcKeyAlgorithm object.
5. Set the name attribute of algorithm to "ECDH".
6. Set the namedCurve attribute of algorithm to equal the namedCurve member of normalizedAlgorithm.
7. Set the [[type]] internal slot of key to "public"
8. Set the [[algorithm]] internal slot of key to algorithm.
Otherwise:

throw a NotSupportedError.
Return key

Export Key

Let key be the CryptoKey to be exported.
If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "spki":
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. Let data be an instance of the subjectPublicKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the algorithm field to an AlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm object identifier to the OID 1.2.840.10045.2.1.
    
    Set the parameters field to an instance of the ECParameters ASN.1 type defined in RFC 5480 as follows:
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
    
    Let keyData be the octet string that represents the Elliptic Curve public key represented by the [[handle]] internal slot of key according to the encoding rules specified in Section 2.2 of RFC 5480 and using the uncompressed form. and keyData.
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp256r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-384":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp384r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-521":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp521r1 defined in RFC 5480
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurveOid and keyData.
    
    Set parameters to the namedCurve choice with value equal to the object identifier namedCurveOid.
  - Set the subjectPublicKey field to keyData.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "pkcs8":
1. If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
2. Let data be an instance of the privateKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the version field to 0.
  - Set the privateKeyAlgorithm field to an PrivateKeyAlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm object identifier to the OID 1.2.840.10045.2.1.
    
    Set the parameters field to an instance of the ECParameters ASN.1 type defined in RFC 5480 as follows:
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
    
    Let keyData be the result of DER-encoding an instance of the ECPrivateKey structure defined in Section 3 of RFC 5915 for the Elliptic Curve private key represented by the [[handle]] internal slot of key and that conforms to the following:
    
    The parameters field is present, and is equivalent to the parameters field of the privateKeyAlgorithm field of this PrivateKeyInfo ASN.1 structure.
    
    The publicKey field is present and represents the Elliptic Curve public key associated with the Elliptic Curve private key represented by the [[handle]] internal slot of key.
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp256r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-384":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp384r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-521":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp521r1 defined in RFC 5480
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurveOid and keyData.
    
    Set parameters to the namedCurve choice with value equal to the object identifier namedCurveOid.
  - Set the privateKey field to keyData.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
1. Let jwk be a new JsonWebKey dictionary.
2. Set the kty attribute of jwk to "EC".
3. If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
  
  If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256":
  
  Set the crv attribute of jwk to "P-256"
  
  If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-384":
  
  Set the crv attribute of jwk to "P-384"
  
  If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-521":
  
  Set the crv attribute of jwk to "P-521"
  
  Set the x attribute of jwk according to the definition in Section 6.2.1.2 of JSON Web Algorithms.
  
  Set the y attribute of jwk according to the definition in Section 6.2.1.3 of JSON Web Algorithms.
  
  If the [[type]] internal slot of key is "private"
  
  Set the d attribute of jwk according to the definition in Section 6.2.2.1 of JSON Web Algorithms.
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurve and a new value of jwk.
  
  Set the crv attribute of jwk to namedCurve.
4. Set the key_ops attribute of jwk to the usages attribute of key.
5. Set the ext attribute of jwk to the [[extractable]] internal slot of key.
6. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
If format is "raw":
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
  
  Let data be an octet string representing the Elliptic Curve point Q represented by [[handle]] internal slot of key according to SEC 1 2.3.3 using the uncompressed format.
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurve and data.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
Otherwise:

throw a NotSupportedError.
Return result.

24. ECDH

24.1. Description

This section is non-normative.

This describes using Elliptic Curve Diffie-Hellman (ECDH) for key generation and key agreement, as specified by RFC6090.

Other specifications may specify the use of additional elliptic curves with ECDH. To specify an additional elliptic curve a specification must define the curve name, ECDH generation steps, ECDH derivation steps, ECDH key import steps and ECDH key export steps.

24.2. Registration

The recognized algorithm name for this algorithm is "ECDH".

Operation	Parameters	Result
generateKey	EcKeyGenParams	CryptoKeyPair
deriveBits	EcdhKeyDeriveParams	Octet string
importKey	EcKeyImportParams	CryptoKey
exportKey	None	object

24.3. EcdhKeyDeriveParams dictionary

IDL


dictionary EcdhKeyDeriveParams : Algorithm {
  // The peer's EC public key.
  required CryptoKey public;
};

24.4. Operations

Generate Key

If usages contains an entry which is not "deriveKey" or "deriveBits" then throw a SyntaxError.
If the namedCurve member of normalizedAlgorithm is "P-256", "P-384" or "P-521":

Generate an Elliptic Curve key pair, as defined in [RFC6090] with domain parameters for the curve identified by the namedCurve member of normalizedAlgorithm.

If the namedCurve member of normalizedAlgorithm is a value specified in an applicable specification that specifies the use of that value with ECDH:

Perform the ECDH key generation steps specified in that specification, passing in normalizedAlgorithm and resulting in an elliptic curve key pair.

Otherwise:

throw a NotSupportedError
If performing the operation results in an error, then throw a OperationError.
Let algorithm be a new EcKeyAlgorithm object.
Set the name member of algorithm to "ECDH".
Set the namedCurve attribute of algorithm to equal the namedCurve member of normalizedAlgorithm.
Let publicKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the public key of the generated key pair.
Set the [[type]] internal slot of publicKey to "public"
Set the [[algorithm]] internal slot of publicKey to algorithm.
Set the [[extractable]] internal slot of publicKey to true.
Set the [[usages]] internal slot of publicKey to be the empty list.
Let privateKey be a new CryptoKey associated with the relevant global object of this [HTML], and representing the private key of the generated key pair.
Set the [[type]] internal slot of privateKey to "private"
Set the [[algorithm]] internal slot of privateKey to algorithm.
Set the [[extractable]] internal slot of privateKey to extractable.
Set the [[usages]] internal slot of privateKey to be the usage intersection of usages and [ "deriveKey", "deriveBits" ].
Let result be a new CryptoKeyPair dictionary.
Set the publicKey attribute of result to be publicKey.
Set the privateKey attribute of result to be privateKey.
Return the result of converting result to an ECMAScript Object, as defined by [WebIDL].

Derive Bits

If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
Let publicKey be the public member of normalizedAlgorithm.
If the [[type]] internal slot of publicKey is not "public", then throw an InvalidAccessError.
If the name attribute of the [[algorithm]] internal slot of publicKey is not equal to the name property of the [[algorithm]] internal slot of key, then throw an InvalidAccessError.
If the namedCurve attribute of the [[algorithm]] internal slot of publicKey is not equal to the namedCurve property of the [[algorithm]] internal slot of key, then throw an InvalidAccessError.
If the namedCurve property of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
1. Perform the ECDH primitive specified in RFC6090 Section 4 with key as the EC private key d and the EC public key represented by the [[handle]] internal slot of publicKey as the EC public key.
2. Let secret be the result of applying the field element to octet string conversion defined in Section 6.2 of RFC6090 to the output of the ECDH primitive.
If the namedCurve property of the [[algorithm]] internal slot of key is a value specified in an applicable specification that specifies the use of that value with ECDH:

Perform the ECDH key derivation steps specified in that specification, passing in key and publicKey and resulting in secret.

Otherwise:

throw a NotSupportedError
If performing the operation results in an error, then throw a OperationError.
If length is null:

Return secret

Otherwise:

If the length of secret in bits is less than length:

throw an OperationError.

Otherwise:

Return an octet string containing the first length bits of secret.

Import Key

Let keyData be the key data to be imported.
If format is "spki":
1. If usages is not empty then throw a SyntaxError.
2. Let spki be the result of running the parse a subjectPublicKeyInfo algorithm over keyData
3. If an error occurred while parsing, then throw a DataError.
4. If the algorithm object identifier field of the algorithm AlgorithmIdentifier field of spki is not equal to the id-ecPublicKey or id-ecDH object identifiers defined in RFC 5480, then throw a DataError.
5. If the parameters field of the algorithm AlgorithmIdentifier field of spki is absent, then throw a DataError.
6. Let params be the parameters field of the algorithm AlgorithmIdentifier field of spki.
7. If params is not an instance of the ECParameters ASN.1 type defined in RFC 5480 that specifies a namedCurve, then throw a DataError.
8. Let namedCurve be a string whose initial value is undefined.
9. If params is equivalent to the secp256r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-256".
  
  If params is equivalent to the secp384r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-384".
  
  If params is equivalent to the secp521r1 object identifier defined in RFC 5480:
  
  Set namedCurve "P-521".
10. If namedCurve is not undefined:
  
  Let publicKey be the Elliptic Curve public key identified by performing the conversion steps defined in Section 2.3.4 of SEC 1 to the subjectPublicKey field of spki.
  
  The uncompressed point format MUST be supported.
  
  If the implementation does not support the compressed point format and a compressed point is provided, throw a DataError.
  
  If a decode error occurs or an identity point is found, throw a DataError.
  
  Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents publicKey.
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, spki and obtaining namedCurve and key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
11. If namedCurve is defined, and not equal to the namedCurve member of normalizedAlgorithm, throw a DataError.
12. If the key value is not a valid point on the Elliptic Curve identified by the namedCurve member of normalizedAlgorithm throw a DataError.
13. Set the [[type]] internal slot of key to "public"
14. Let algorithm be a new EcKeyAlgorithm.
15. Set the name attribute of algorithm to "ECDH".
16. Set the namedCurve attribute of algorithm to namedCurve.
17. Set the [[algorithm]] internal slot of key to algorithm.
If format is "pkcs8":
1. If usages contains an entry which is not "deriveKey" or "deriveBits" then throw a SyntaxError.
2. Let privateKeyInfo be the result of running the parse a privateKeyInfo algorithm over keyData.
3. If an error occurs while parsing, throw a DataError.
4. If the algorithm object identifier field of the privateKeyAlgorithm PrivateKeyAlgorithm field of privateKeyInfo is not equal to the id-ecPublicKey or id-ecDH object identifiers defined in RFC 5480, throw a DataError.
5. If the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo is not present, throw a DataError.
6. Let params be the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
7. If params is not an instance of the ECParameters ASN.1 type defined in RFC 5480 that specifies a namedCurve, then throw a DataError.
8. Let namedCurve be a string whose initial value is undefined.
9. If params is equivalent to the secp256r1 object identifier defined in RFC 5480:
  
  Set namedCurve to "P-256".
  
  If params is equivalent to the secp384r1 object identifier defined in RFC 5480:
  
  Set namedCurve to "P-384".
  
  If params is equivalent to the secp521r1 object identifier defined in RFC 5480:
  
  Set namedCurve to "P-521".
10. If namedCurve is not undefined:
  
  Let ecPrivateKey be the result of performing the parse an ASN.1 structure algorithm, with data as the privateKey field of privateKeyInfo, structure as the ASN.1 ECPrivateKey structure specified in Section 3 of RFC 5915, and exactData set to true.
  
  If an error occurred while parsing, then throw a DataError.
  
  If the parameters field of ecPrivateKey is present, and is not an instance of the namedCurve ASN.1 type defined in RFC 5480, or does not contain the same object identifier as the parameters field of the privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo, throw a DataError.
  
  Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents the Elliptic Curve private key identified by performing the conversion steps defined in Section 3 of RFC 5915 using ecPrivateKey.
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, privateKeyInfo and obtaining namedCurve and key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
11. If namedCurve is defined, and not equal to the namedCurve member of normalizedAlgorithm, throw a DataError.
12. If the key value is not a valid point on the Elliptic Curve identified by the namedCurve member of normalizedAlgorithm throw a DataError.
13. Set the [[type]] internal slot of key to "private".
14. Let algorithm be a new EcKeyAlgorithm.
15. Set the name attribute of algorithm to "ECDH".
16. Set the namedCurve attribute of algorithm to namedCurve.
17. Set the [[algorithm]] internal slot of key to algorithm.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "d" field is present and if usages contains an entry which is not "deriveKey" or "deriveBits" then throw a SyntaxError.
3. If the "d" field is not present and if usages is not empty then throw a SyntaxError.
4. If the "kty" field of jwk is not "EC", then throw a DataError.
5. If usages is non-empty and the "use" field of jwk is present and is not equal to "enc" then throw a DataError.
6. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key, or it does not contain all of the specified usages values, then throw a DataError.
7. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
8. Let namedCurve be a string whose value is equal to the "crv" field of jwk.
9. If namedCurve is not equal to the namedCurve member of normalizedAlgorithm, throw a DataError.
10. If namedCurve is "P-256", "P-384" or "P-521":
  
  If the "d" field is present:
  
  If jwk does not meet the requirements of Section 6.2.2 of JSON Web Algorithms, then throw a DataError.
  
  Let key be a new CryptoKey object that represents the Elliptic Curve private key identified by interpreting jwk according to Section 6.2.2 of JSON Web Algorithms.
  
  Set the [[type]] internal slot of Key to "private".
  
  Otherwise:
  
  If jwk does not meet the requirements of Section 6.2.1 of JSON Web Algorithms, then throw a DataError.
  
  Let key be a new CryptoKey object that represents the Elliptic Curve public key identified by interpreting jwk according to Section 6.2.1 of JSON Web Algorithms.
  
  Set the [[type]] internal slot of Key to "public".
  
  Otherwise
  
  Perform any key import steps defined by other applicable specifications, passing format, jwk and obtaining key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
11. If the key value is not a valid point on the Elliptic Curve identified by the namedCurve member of normalizedAlgorithm throw a DataError.
12. Let algorithm be a new instance of an EcKeyAlgorithm object.
13. Set the name attribute of algorithm to "ECDH".
14. Set the namedCurve attribute of algorithm to namedCurve.
15. Set the [[algorithm]] internal slot of key to algorithm.
If format is "raw":
1. If the namedCurve member of normalizedAlgorithm is not a named curve, then throw a DataError.
2. If usages is not the empty list, then throw a SyntaxError.
3. If namedCurve is "P-256", "P-384" or "P-521":
  
  Let Q be the Elliptic Curve public key on the curve identified by the namedCurve member of normalizedAlgorithm identified by performing the conversion steps defined in Section 2.3.4 of SEC 1 to keyData.
  
  The uncompressed point format MUST be supported.
  
  If the implementation does not support the compressed point format and a compressed point is provided, throw a DataError.
  
  If a decode error occurs or an identity point is found, throw a DataError.
  
  Let key be a new CryptoKey associated with the relevant global object of this [HTML], and that represents Q.
  
  Otherwise:
  
  Perform any key import steps defined by other applicable specifications, passing format, keyData and obtaining key.
  
  If an error occured or there are no applicable specifications, throw a DataError.
4. Let algorithm be a new EcKeyAlgorithm object.
5. Set the name attribute of algorithm to "ECDH".
6. Set the namedCurve attribute of algorithm to equal the namedCurve member of normalizedAlgorithm.
7. Set the [[type]] internal slot of key to "public"
8. Set the [[algorithm]] internal slot of key to algorithm.
Return key

Export Key

Let key be the CryptoKey to be exported.
If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "spki":
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. Let data be an instance of the subjectPublicKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the algorithm field to an AlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm object identifier to the OID 1.3.132.1.12.
    
    Set the parameters field to an instance of the ECParameters ASN.1 type defined in RFC 5480 as follows:
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
    
    Let keyData be the octet string that represents the Elliptic Curve public key represented by the [[handle]] internal slot of key according to the encoding rules specified in Section 2.3.3 of SEC 1 and using the uncompressed form.
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp256r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-384":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp384r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-521":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp521r1 defined in RFC 5480
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurveOid and keyData.
    
    Set parameters to the namedCurve choice with value equal to the object identifier namedCurveOid.
  - Set the subjectPublicKey field to keyData
If format is "pkcs8":
1. If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
2. Let data be an instance of the privateKeyInfo ASN.1 structure defined in RFC 5280 with the following properties:
  - Set the version field to 0.
  - Set the privateKeyAlgorithm field to an PrivateKeyAlgorithmIdentifier ASN.1 type with the following properties:
    
    Set the algorithm object identifier to the OID 1.3.132.1.12.
    
    Set the parameters field to an instance of the ECParameters ASN.1 type defined in RFC 5480 as follows:
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
    
    Let keyData be the result of DER-encoding an instance of the ECPrivateKey structure defined in Section 3 of RFC 5915 for the Elliptic Curve private key represented by the [[handle]] internal slot of key and that conforms to the following:
    
    The parameters field is present, and is equivalent to the parameters field of the privateKeyAlgorithm field of this PrivateKeyInfo ASN.1 structure.
    
    The publicKey field is present and represents the Elliptic Curve public key associated with the Elliptic Curve private key represented by the [[handle]] internal slot of key.
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp256r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-384":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp384r1 defined in RFC 5480
    
    If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-521":
    
    Set parameters to the namedCurve choice with value equal to the object identifier secp521r1 defined in RFC 5480
    
    Otherwise:
    
    Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurveOid and keyData.
    
    Set parameters to the namedCurve choice with value equal to the object identifier namedCurveOid.
  - Set the privateKey field to keyData.
If format is "jwk":
1. Let jwk be a new JsonWebKey dictionary.
2. Set the kty attribute of jwk to "EC".
3. If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
  
  If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256":
  
  Set the crv attribute of jwk to "P-256"
  
  If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-384":
  
  Set the crv attribute of jwk to "P-384"
  
  If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-521":
  
  Set the crv attribute of jwk to "P-521"
  
  Set the x attribute of jwk according to the definition in Section 6.2.1.2 of JSON Web Algorithms.
  
  Set the y attribute of jwk according to the definition in Section 6.2.1.3 of JSON Web Algorithms.
  
  If the [[type]] internal slot of key is "private"
  
  Set the d attribute of jwk according to the definition in Section 6.2.2.1 of JSON Web Algorithms.
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurve and a new value of jwk.
  
  Set the crv attribute of jwk to namedCurve.
4. Set the key_ops attribute of jwk to the usages attribute of key.
5. Set the ext attribute of jwk to the [[extractable]] internal slot of key.
6. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
If format is "raw":
1. If the [[type]] internal slot of key is not "public", then throw an InvalidAccessError.
2. If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
  
  Let data be the octet string that represents the Elliptic Curve public key represented by the [[handle]] internal slot of key according to the encoding rules specified in Section 2.3.3 of SEC 1 and using the uncompressed form.
  
  Otherwise:
  
  Perform any key export steps defined by other applicable specifications, passing format and the namedCurve attribute of the [[algorithm]] internal slot of key and obtaining namedCurve and data.
3. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
Return result.

25. AES-CTR

25.1. Description

This section is non-normative.

The "AES-CTR" algorithm identifier is used to perform encryption and decryption using AES in Counter mode, as described in [NIST SP800-38A].

25.2. Registration

The recognized algorithm name for this algorithm is "AES-CTR".

Operation	Parameters	Result
encrypt	AesCtrParams	ArrayBuffer
decrypt	AesCtrParams	ArrayBuffer
generateKey	AesKeyGenParams	CryptoKey
importKey	None	CryptoKey
exportKey	None	object
get key length	AesDerivedKeyParams	Integer

25.3. AesCtrParams dictionary

IDL


dictionary AesCtrParams : Algorithm {
  // The initial value of the counter block. counter MUST be 16 bytes
  // (the AES block size). The counter bits are the rightmost length
  // bits of the counter block. The rest of the counter block is for
  // the nonce. The counter bits are incremented using the standard
  // incrementing function specified in NIST SP 800-38A Appendix B.1:
  // the counter bits are interpreted as a big-endian integer and
  // incremented by one.
  required BufferSource counter;
  // The length, in bits, of the rightmost part of the counter block
  // that is incremented.
  [EnforceRange] required octet length;
};

IDL


dictionary AesKeyAlgorithm : KeyAlgorithm {
  // The length, in bits, of the key.
  required unsigned short length;
};

25.5. AesKeyGenParams dictionary

IDL


dictionary AesKeyGenParams : Algorithm {
  // The length, in bits, of the key.
  [EnforceRange] required unsigned short length;
};

25.6. AesDerivedKeyParams dictionary

IDL


dictionary AesDerivedKeyParams : Algorithm {
  // The length, in bits, of the key.
  [EnforceRange] required unsigned short length;
};

25.7. Operations

Encrypt

If the counter member of normalizedAlgorithm does not have length 16 bytes, then throw an OperationError.
If the length member of normalizedAlgorithm is zero or is greater than 128, then throw an OperationError.
Let ciphertext be the result of performing the CTR Encryption operation described in Section 6.5 of [NIST SP800-38A] using AES as the block cipher, the contents of the counter member of normalizedAlgorithm as the initial value of the counter block, the length member of normalizedAlgorithm as the input parameter m to the standard counter block incrementing function defined in Appendix B.1 of [NIST SP800-38A] and the contents of plaintext as the input plaintext.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing ciphertext.

Decrypt

If the counter member of normalizedAlgorithm does not have length 16 bytes, then throw an OperationError.
If the length member of normalizedAlgorithm is zero or is greater than 128, then throw an OperationError.
Let plaintext be the result of performing the CTR Decryption operation described in Section 6.5 of [NIST SP800-38A] using AES as the block cipher, the contents of the counter member of normalizedAlgorithm as the initial value of the counter block, the length member of normalizedAlgorithm as the input parameter m to the standard counter block incrementing function defined in Appendix B.1 of [NIST SP800-38A] and the contents of ciphertext as the input ciphertext.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing plaintext.

Generate Key

If usages contains any entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
If the length member of normalizedAlgorithm is not equal to one of 128, 192 or 256, then throw an OperationError.
Generate an AES key of length equal to the length member of normalizedAlgorithm.
If the key generation step fails, then throw an OperationError.
Let key be a new CryptoKey object representing the generated AES key.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-CTR".
Set the length attribute of algorithm to equal the length member of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm.
Set the [[extractable]] internal slot of key to be extractable.
Set the [[usages]] internal slot of key to be usages.
Return key.

Import Key

If usages contains an entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
If format is "raw":
1. Let data be the octet string contained in keyData.
2. If the length in bits of data is not 128, 192 or 256 then throw a DataError.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "kty" field of jwk is not "oct", then throw a DataError.
3. If jwk does not meet the requirements of Section 6.4 of JSON Web Algorithms, then throw a DataError.
4. Let data be the octet string obtained by decoding the "k" field of jwk.
5. If data has length 128 bits:
  
  If the "alg" field of jwk is present, and is not "A128CTR", then throw a DataError.
  
  If data has length 192 bits:
  
  If the "alg" field of jwk is present, and is not "A192CTR", then throw a DataError.
  
  If data has length 256 bits:
  
  If the "alg" field of jwk is present, and is not "A256CTR", then throw a DataError.
  
  Otherwise:
  
  throw a DataError.
6. If usages is non-empty and the "use" field of jwk is present and is not "enc", then throw a DataError.
7. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
8. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
Otherwise:

throw a NotSupportedError.
Let key be a new CryptoKey object representing an AES key with value data.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-CTR".
Set the length attribute of algorithm to the length, in bits, of data.
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Export Key

If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "raw":
1. Let data be the raw octets of the key represented by [[handle]] internal slot of key.
2. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
1. Let jwk be a new JsonWebKey dictionary.
2. Set the kty attribute of jwk to the string "oct".
3. Set the k attribute of jwk to be a string containing the raw octets of the key represented by [[handle]] internal slot of key, encoded according to Section 6.4 of JSON Web Algorithms.
4. If the length attribute of key is 128:
  
  Set the alg attribute of jwk to the string "A128CTR".
  
  If the length attribute of key is 192:
  
  Set the alg attribute of jwk to the string "A192CTR".
  
  If the length attribute of key is 256:
  
  Set the alg attribute of jwk to the string "A256CTR".
5. Set the key_ops attribute of jwk to equal the [[usages]] internal slot of key.
6. Set the ext attribute of jwk to equal the [[extractable]] internal slot of key.
7. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise:

throw a NotSupportedError.
Return result.

Get key length

If the length member of normalizedDerivedKeyAlgorithm is not 128, 192 or 256, then throw a OperationError.
Return the length member of normalizedDerivedKeyAlgorithm.

26. AES-CBC

26.1. Description

This section is non-normative.

The "AES-CBC" algorithm identifier is used to perform encryption and decryption using AES in Cipher Block Chaining mode, as described in [NIST SP800-38A].

When operating in CBC mode, messages that are not exact multiples of the AES block size (16 bytes) can be padded under a variety of padding schemes. In the Web Crypto API, the only padding mode that is supported is that of PKCS#7, as described by Section 10.3, step 2, of [RFC2315].

26.2. Registration

The recognized algorithm name for this algorithm is "AES-CBC".

Operation	Parameters	Result
encrypt	AesCbcParams	ArrayBuffer
decrypt	AesCbcParams	ArrayBuffer
generateKey	AesKeyGenParams	CryptoKey
importKey	None	CryptoKey
exportKey	None	object
get key length	AesDerivedKeyParams	Integer

26.3. AesCbcParams dictionary

IDL


dictionary AesCbcParams : Algorithm {
  // The initialization vector. MUST be 16 bytes.
  required BufferSource iv;
};

26.4. Operations

Encrypt

If the iv member of normalizedAlgorithm does not have length 16 bytes, then throw an OperationError.
Let paddedPlaintext be the result of adding padding octets to the contents of ciphertext according to the procedure defined in Section 10.3 of [RFC2315], step 2, with a value of k of 16.
Let ciphertext be the result of performing the CBC Encryption operation described in Section 6.2 of [NIST SP800-38A] using AES as the block cipher, the contents of the iv member of normalizedAlgorithm as the IV input parameter and paddedPlaintext as the input plaintext.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing ciphertext.

Decrypt

If the iv member of normalizedAlgorithm does not have length 16 bytes, then throw an OperationError.
Let paddedPlaintext be the result of performing the CBC Decryption operation described in Section 6.2 of [NIST SP800-38A] using AES as the block cipher, the contents of the iv member of normalizedAlgorithm as the IV input parameter and the contents of ciphertext as the input ciphertext.
Let p be the value of the last octet of paddedPlaintext.
If p is zero or greater than 16, or if any of the last p octets of paddedPlaintext have a value which is not p, then throw an OperationError.
Let plaintext be the result of removing p octets from the end of paddedPlaintext.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing plaintext.

Generate Key

If usages contains any entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
If the length member of normalizedAlgorithm is not equal to one of 128, 192 or 256, then throw an OperationError.
Generate an AES key of length equal to the length member of normalizedAlgorithm.
If the key generation step fails, then throw an OperationError.
Let key be a new CryptoKey object representing the generated AES key.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-CBC".
Set the length attribute of algorithm to equal the length member of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm.
Set the [[extractable]] internal slot of key to be extractable.
Set the [[usages]] internal slot of key to be usages.
Return key.

Import Key

If usages contains an entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
If format is "raw":
1. Let data be the octet string contained in keyData.
2. If the length in bits of data is not 128, 192 or 256 then throw a DataError.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "kty" field of jwk is not "oct", then throw a DataError.
3. If jwk does not meet the requirements of Section 6.4 of JSON Web Algorithms, then throw a DataError.
4. Let data be the octet string obtained by decoding the "k" field of jwk.
5. If data has length 128 bits:
  
  If the "alg" field of jwk is present, and is not "A128CBC", then throw a DataError.
  
  If data has length 192 bits:
  
  If the "alg" field of jwk is present, and is not "A192CBC", then throw a DataError.
  
  If data has length 256 bits:
  
  If the "alg" field of jwk is present, and is not "A256CBC", then throw a DataError.
  
  Otherwise:
  
  throw a DataError.
6. If usages is non-empty and the "use" field of jwk is present and is not "enc", then throw a DataError.
7. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
8. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
Otherwise:

throw a NotSupportedError
Let key be a new CryptoKey object representing an AES key with value data.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-CBC".
Set the length attribute of algorithm to the length, in bits, of data.
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Export Key

If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "raw":
1. Let data be the raw octets of the key represented by [[handle]] internal slot of key.
2. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. Set the kty attribute of jwk to the string "oct".
3. Set the k attribute of jwk to be a string containing the raw octets of the key represented by [[handle]] internal slot of key, encoded according to Section 6.4 of JSON Web Algorithms.
4. If the length attribute of key is 128:
  
  Set the alg attribute of jwk to the string "A128CBC".
  
  If the length attribute of key is 192:
  
  Set the alg attribute of jwk to the string "A192CBC".
  
  If the length attribute of key is 256:
  
  Set the alg attribute of jwk to the string "A256CBC".
5. Set the key_ops attribute of jwk to equal the usages attribute of key.
6. Set the ext attribute of jwk to equal the [[extractable]] internal slot of key.
7. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise:

throw a NotSupportedError.
Return result.

Get key length

If the length member of normalizedDerivedKeyAlgorithm is not 128, 192 or 256, then throw an OperationError.
Return the length member of normalizedDerivedKeyAlgorithm.

27. AES-GCM

27.1. Description

This section is non-normative.

The "AES-GCM" algorithm identifier is used to perform authenticated encryption and decryption using AES in Galois/Counter Mode mode, as described in [NIST SP 800-38D].

27.2. Registration

The recognized algorithm name for this algorithm is "AES-GCM".

Operation	Parameters	Result
encrypt	AesGcmParams	ArrayBuffer
decrypt	AesGcmParams	ArrayBuffer
generateKey	AesKeyGenParams	CryptoKey
importKey	None	CryptoKey
exportKey	None	object
get key length	AesDerivedKeyParams	Integer

27.3. AesGcmParams dictionary

IDL


dictionary AesGcmParams : Algorithm {
  // The initialization vector to use. May be up to 2^64-1 bytes long.
  required BufferSource iv;
  // The additional authentication data to include.
  BufferSource additionalData;
  // The desired length of the authentication tag. May be 0 - 128.
  [EnforceRange] octet tagLength;
};

27.4. Operations

Encrypt

If plaintext has a length greater than 2^39 - 256 bytes, then throw an OperationError.
If the iv member of normalizedAlgorithm has a length greater than 2^64 - 1 bytes, then throw an OperationError.
If the additionalData member of normalizedAlgorithm is present and has a length greater than 2^64 - 1 bytes, then throw an OperationError.
If the tagLength member of normalizedAlgorithm is not present:

Let tagLength be 128.

If the tagLength member of normalizedAlgorithm is one of 32, 64, 96, 104, 112, 120 or 128:

Let tagLength be equal to the tagLength member of normalizedAlgorithm

Otherwise:

throw an OperationError.
Let additionalData be the contents of the additionalData member of normalizedAlgorithm if present or the empty octet string otherwise.
Let C and T be the outputs that result from performing the Authenticated Encryption Function described in Section 7.1 of [NIST SP800-38D] using AES as the block cipher, the contents of the iv member of normalizedAlgorithm as the IV input parameter, the contents of additionalData as the A input parameter, tagLength as the t pre-requisite and the contents of plaintext as the input plaintext.
Let ciphertext be equal to C | T, where '|' denotes concatenation.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing ciphertext.

Decrypt

If the tagLength member of normalizedAlgorithm is not present:

Let tagLength be 128.

If the tagLength member of normalizedAlgorithm is one of 32, 64, 96, 104, 112, 120 or 128:

Let tagLength be equal to the tagLength member of normalizedAlgorithm

Otherwise:

throw an OperationError.
If plaintext has a length less than tagLength bits, then throw an OperationError.
If the iv member of normalizedAlgorithm has a length greater than 2^64 - 1 bytes, then throw an OperationError.
If the additionalData member of normalizedAlgorithm is present and has a length greater than 2^64 - 1 bytes, then throw an OperationError.
Let tag be the last tagLength bits of ciphertext.
Let actualCiphertext be the result of removing the last tagLength bits from ciphertext.
Let additionalData be the contents of the additionalData member of normalizedAlgorithm if present or the empty octet string otherwise.
Perform the Authenticated Decryption Function described in Section 7.2 of [NIST SP800-38D] using AES as the block cipher, the contents of the iv member of normalizedAlgorithm as the IV input parameter, the contents of additionalData as the A input parameter, tagLength as the t pre-requisite, the contents of actualCiphertext as the input ciphertext, C and the contents of tag as the authentication tag, T.

If the result of the algorithm is the indication of inauthenticity, "FAIL":

throw an OperationError

Otherwise:

Let plaintext be the output P of the Authenticated Decryption Function.
Return a new ArrayBuffer associated with the relevant global object of this [HTML], and containing plaintext.

Generate Key

If usages contains any entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
If the length member of normalizedAlgorithm is not equal to one of 128, 192 or 256, then throw an OperationError.
Generate an AES key of length equal to the length member of normalizedAlgorithm.
If the key generation step fails, then throw an OperationError.
Let key be a new CryptoKey object representing the generated AES key.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-GCM".
Set the length attribute of algorithm to equal the length member of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm.
Set the [[extractable]] internal slot of key to be extractable.
Set the [[usages]] internal slot of key to be usages.
Return key.

Import Key

If usages contains an entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
If format is "raw":
1. Let data be the octet string contained in keyData.
2. If the length in bits of data is not 128, 192 or 256 then throw a DataError.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "kty" field of jwk is not "oct", then throw a DataError.
3. If jwk does not meet the requirements of Section 6.4 of JSON Web Algorithms, then throw a DataError.
4. Let data be the octet string obtained by decoding the "k" field of jwk.
5. If data has length 128 bits:
  
  If the "alg" field of jwk is present, and is not "A128GCM", then throw a DataError.
  
  If data has length 192 bits:
  
  If the "alg" field of jwk is present, and is not "A192GCM", then throw a DataError.
  
  If data has length 256 bits:
  
  If the "alg" field of jwk is present, and is not "A256GCM", then throw a DataError.
  
  Otherwise:
  
  throw a DataError.
6. If usages is non-empty and the "use" field of jwk is present and is not "enc", then throw a DataError.
7. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
8. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
Otherwise:

throw a NotSupportedError.
Let key be a new CryptoKey object representing an AES key with value data.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-GCM".
Set the length attribute of algorithm to the length, in bits, of data.
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Export Key

If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "raw":
1. Let data be the raw octets of the key represented by [[handle]] internal slot of key.
2. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
1. Let jwk be a new JsonWebKey dictionary.
2. Set the kty attribute of jwk to the string "oct".
3. Set the k attribute of jwk to be a string containing the raw octets of the key represented by [[handle]] internal slot of key, encoded according to Section 6.4 of JSON Web Algorithms.
4. If the length attribute of key is 128:
  
  Set the alg attribute of jwk to the string "A128GCM".
  
  If the length attribute of key is 192:
  
  Set the alg attribute of jwk to the string "A192GCM".
  
  If the length attribute of key is 256:
  
  Set the alg attribute of jwk to the string "A256GCM".
5. Set the key_ops attribute of jwk to equal the usages attribute of key.
6. Set the ext attribute of jwk to equal the [[extractable]] internal slot of key.
7. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise:

throw a NotSupportedError.
Return result.

Get key length

If the length member of normalizedDerivedKeyAlgorithm is not 128, 192 or 256, then throw an OperationError.
Return the length member of normalizedDerivedKeyAlgorithm.

28. AES-KW

28.1. Description

This section is non-normative.

The "AES-KW" algorithm identifier is used to perform key wrapping using AES, as described in [RFC3394].

28.2. Registration

The recognized algorithm name for this algorithm is "AES-KW".

Operation	Parameters	Result
wrapKey	None	ArrayBuffer
unwrapKey	None	ArrayBuffer
generateKey	AesKeyGenParams	CryptoKey
importKey	None	CryptoKey
exportKey	None	object
get key length	AesDerivedKeyParams	Integer

28.3. Operations

Wrap Key

If plaintext is not a multiple of 64 bits in length, then throw an OperationError.
Let ciphertext be the result of performing the Key Wrap operation described in Section 2.2.1 of [RFC3394] with plaintext as the plaintext to be wrapped and using the default Initial Value defined in Section 2.2.3.1 of the same document.
Return ciphertext.

Unwrap Key

Let plaintext be the result of performing the Key Unwrap operation described in Section 2.2.2 of [RFC3394] with ciphertext as the input ciphertext and using the default Initial Value defined in Section 2.2.3.1 of the same document.
If the Key Unwrap operation returns an error, then throw an OperationError.
Return plaintext.

Generate Key

If usages contains any entry which is not one of "wrapKey" or "unwrapKey", then throw a SyntaxError.
If the length property of normalizedAlgorithm is not equal to one of 128, 192 or 256, then throw an OperationError.
If the key generation step fails, then throw an OperationError.
Let key be a new CryptoKey object representing the generated AES key.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-KW".
Set the length attribute of algorithm to equal the length property of normalizedAlgorithm.
Set the [[algorithm]] internal slot of key to algorithm.
Set the [[extractable]] internal slot of key to be extractable.
Set the [[usages]] internal slot of key to be usages.
Return key.

Import Key

If usages contains an entry which is not one of "wrapKey" or "unwrapKey", then throw a SyntaxError.
If format is "raw":
1. Let data be the octet string contained in keyData.
2. If the length in bits of data is not 128, 192 or 256 then throw a DataError.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "kty" field of jwk is not "oct", then throw a DataError.
3. If jwk does not meet the requirements of Section 6.4 of JSON Web Algorithms, then throw a DataError.
4. Let data be the octet string obtained by decoding the "k" field of jwk.
5. If data has length 128 bits:
  
  If the "alg" field of jwk is present, and is not "A128KW", then throw a DataError.
  
  If data has length 192 bits:
  
  If the "alg" field of jwk is present, and is not "A192KW", then throw a DataError.
  
  If data has length 256 bits:
  
  If the "alg" field of jwk is present, and is not "A256KW", then throw a DataError.
  
  Otherwise:
  
  throw a DataError.
6. If usages is non-empty and the "use" field of jwk is present and is not "enc", then throw a DataError.
7. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
8. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
Otherwise:

throw a NotSupportedError.
Let key be a new CryptoKey associated with the relevant global object of this [HTML], and representing an AES key with value data.
Let algorithm be a new AesKeyAlgorithm.
Set the name attribute of algorithm to "AES-KW".
Set the length attribute of algorithm to the length, in bits, of data.
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Export Key

If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
If format is "raw":
1. Let data be the raw octets of the key represented by [[handle]] internal slot of key.
2. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
1. Let jwk be a new JsonWebKey dictionary.
2. Set the kty attribute of jwk to the string "oct".
3. Set the k attribute of jwk to be a string containing the raw octets of the key represented by [[handle]] internal slot of key, encoded according to Section 6.4 of JSON Web Algorithms.
4. If the length attribute of key is 128:
  
  Set the alg attribute of jwk to the string "A128KW".
  
  If the length attribute of key is 192:
  
  Set the alg attribute of jwk to the string "A192KW".
  
  If the length attribute of key is 256:
  
  Set the alg attribute of jwk to the string "A256KW".
5. Set the key_ops attribute of jwk to equal the usages attribute of key.
6. Set the ext attribute of jwk to equal the [[extractable]] internal slot of key.
7. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise:

throw a NotSupportedError.
Return result.

Get key length

If the length member of normalizedDerivedKeyAlgorithm is not 128, 192 or 256, then throw an OperationError.
Return the length member of normalizedDerivedKeyAlgorithm.

29. HMAC

29.1. Description

This section is non-normative.

The HMAC algorithm calculates and verifies hash-based message authentication codes according to [FIPS PUB 198-1] using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with HMAC. Such specifications must define the digest operation for the additional hash algorithms and key import steps and key export steps for HMAC.

29.2. Registration

The recognized algorithm name for this algorithm is "HMAC".

Operation	Parameters	Result
sign	None	ArrayBuffer
verify	None	boolean
generateKey	HmacKeyGenParams	CryptoKey
importKey	HmacImportParams	CryptoKey
exportKey	None	object
get key length	HmacImportParams	Integer

29.3. HmacImportParams dictionary

IDL


dictionary HmacImportParams : Algorithm {
  // The inner hash function to use.
  required HashAlgorithmIdentifier hash;
  // The length (in bits) of the key.
  [EnforceRange] unsigned long length;
};

29.4. HmacKeyAlgorithm dictionary

IDL


dictionary HmacKeyAlgorithm : KeyAlgorithm {
  // The inner hash function to use.
  required KeyAlgorithm hash;
  // The length (in bits) of the key.
  required unsigned long length;
};

29.5. HmacKeyGenParams dictionary

IDL


dictionary HmacKeyGenParams : Algorithm {
  // The inner hash function to use.
  required HashAlgorithmIdentifier hash;
  // The length (in bits) of the key to generate. If unspecified, the
  // recommended length will be used, which is the size of the associated hash function's block
  // size.
  [EnforceRange] unsigned long length;
};

29.6. Operations

Sign

Let mac be the result of performing the MAC Generation operation described in Section 4 of [FIPS PUB 198-1] using the key represented by [[handle]] internal slot of key, the hash function identified by the hash attribute of the [[algorithm]] internal slot of key and message as the input data text.
Return a new ArrayBuffer object, associated with the relevant global object of this [HTML], and containing the bytes of mac.

Verify

Let mac be the result of performing the MAC Generation operation described in Section 4 of [FIPS PUB 198-1] using the key represented by [[handle]] internal slot of key, the hash function identified by the hash attribute of the [[algorithm]] internal slot of key and message as the input data text.
Return true if mac is equal to signature and false otherwise.

Generate Key

If usages contains any entry which is not "sign" or "verify", then throw a SyntaxError.
If the length member of normalizedAlgorithm is not present:

Let length be the block size in bits of the hash function identified by the hash member of normalizedAlgorithm.

Otherwise, if the length member of normalizedAlgorithm is non-zero:

Let length be equal to the length member of normalizedAlgorithm.

Otherwise:

throw an OperationError.
Generate a key of length length bits.
If the key generation step fails, then throw an OperationError.
Let key be a new CryptoKey object representing the generated key.
Let algorithm be a new HmacKeyAlgorithm.
Set the name attribute of algorithm to "HMAC".
Let hash be a new KeyAlgorithm.
Set the name attribute of hash to equal the name member of the hash member of normalizedAlgorithm.
Set the hash attribute of algorithm to hash.
Set the [[algorithm]] internal slot of key to algorithm.
Set the [[extractable]] internal slot of key to be extractable.
Set the [[usages]] internal slot of key to be usages.
Return key.

Import Key

Let keyData be the key data to be imported.
If usages contains an entry which is not "sign" or "verify", then throw a SyntaxError.
Let hash be a new KeyAlgorithm.
If format is "raw":
1. Let data be the octet string contained in keyData.
2. Set hash to equal the hash member of normalizedAlgorithm.
If format is "jwk":
1. If keyData is a JsonWebKey dictionary:
  
  Let jwk equal keyData.
  
  Otherwise:
  
  Throw a DataError.
2. If the "kty" field of jwk is not "oct", then throw a DataError.
3. If jwk does not meet the requirements of Section 6.4 of JSON Web Algorithms, then throw a DataError.
4. Let data be the octet string obtained by decoding the "k" field of jwk.
5. Set the hash to equal the hash member of normalizedAlgorithm.
6. If the name attribute of hash is "SHA-1":
  
  If the "alg" field of jwk is present and is not "HS1", then throw a DataError.
  
  If If the name attribute of hash is "SHA-256":
  
  If the "alg" field of jwk is present and is not "HS256", then throw a DataError.
  
  If If the name attribute of hash is "SHA-384":
  
  If the "alg" field of jwk is present and is not "HS384", then throw a DataError.
  
  If If the name attribute of hash is "SHA-512":
  
  If the "alg" field of jwk is present and is not "HS512", then throw a DataError.
  
  Otherwise, if the name attribute of hash is defined in another applicable specification:
  
  Perform any key import steps defined by other applicable specifications, passing format, jwk and hash and obtaining hash.
7. If usages is non-empty and the "use" field of jwk is present and is not "sign", then throw a DataError.
8. If the "key_ops" field of jwk is present, and is invalid according to the requirements of JSON Web Key or does not contain all of the specified usages values, then throw a DataError.
9. If the "ext" field of jwk is present and has the value false and extractable is true, then throw a DataError.
Otherwise:

throw a NotSupportedError.
Let length be equivalent to the length, in octets, of data, multiplied by 8.
If length is zero then throw a DataError.
If the length member of normalizedAlgorithm is present:

If the length member of normalizedAlgorithm is greater than length:

throw a DataError.

If the length member of normalizedAlgorithm, is less than or equal to length minus eight:

throw a DataError.

Otherwise:

Set length equal to the length member of normalizedAlgorithm.
Let key be a new CryptoKey object representing an HMAC key with the first length bits of data.
Let algorithm be a new HmacKeyAlgorithm.
Set the name attribute of algorithm to "HMAC".
Set the length attribute of algorithm to length.
Set the hash attribute of algorithm to hash.
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Export Key

If the underlying cryptographic key material represented by the [[handle]] internal slot of key cannot be accessed, then throw an OperationError.
Let bits be the raw bits of the key represented by [[handle]] internal slot of key.
Let data be an octet string containing bits.
If format is "raw":
1. Let result be a new ArrayBuffer associated with the relevant global object of this [HTML], and containing data.
If format is "jwk":
1. Let jwk be a new JsonWebKey dictionary.
2. Set the kty attribute of jwk to the string "oct".
3. Set the k attribute of jwk to be a string containing data, encoded according to Section 6.4 of JSON Web Algorithms.
4. Let algorithm be the [[algorithm]] internal slot of key.
5. Let hash be the hash attribute of algorithm.
6. If the name attribute of hash is "SHA-1":
  
  Set the alg attribute of jwk to the string "HS1".
  
  If the name attribute of hash is "SHA-256":
  
  Set the alg attribute of jwk to the string "HS256".
  
  If the name attribute of hash is "SHA-384":
  
  Set the alg attribute of jwk to the string "HS384".
  
  If the name attribute of hash is "SHA-512":
  
  Set the alg attribute of jwk to the string "HS512".
  
  Otherwise, the name attribute of hash is defined in another applicable specification:
  
  Perform any key export steps defined by other applicable specifications, passing format and key and obtaining alg.
  
  Set the alg attribute of jwk to alg.
7. Set the key_ops attribute of jwk to equal the usages attribute of key.
8. Set the ext attribute of jwk to equal the [[extractable]] internal slot of key.
9. Let result be the result of converting jwk to an ECMAScript Object, as defined by [WebIDL].
Otherwise:

throw a NotSupportedError.
Return result.

Get key length

If the length member of normalizedDerivedKeyAlgorithm is not present:

Let length be the block size in bytes of the hash function identified by the hash member of normalizedDerivedKeyAlgorithm.

Otherwise, if the length member of normalizedDerivedKeyAlgorithm is non-zero:

Let length be equal to the length member of normalizedDerivedKeyAlgorithm.

Otherwise:

throw a TypeError.
Return length.

30. SHA

30.1. Description

This section is non-normative.

This describes the SHA-1 and SHA-2 families, as specified by [FIPS PUB 180-4].

30.2. Registration

The following algorithms are added as recognized algorithm names:

"SHA-1": The SHA-1 algorithm as specified in Section 6.1
"SHA-256": The SHA-256 algorithm as specified in Section 6.2
"SHA-384": The SHA-384 algorithm as specified in Section 6.5
"SHA-512": The SHA-512 algorithm as specified in Section 6.4

Operation	Parameters	Result
digest	None	ArrayBuffer

30.3. Operations

Digest

If the name member of normalizedAlgorithm is a cases-sensitive string match for "SHA-1":

Let result be the result of performing the SHA-1 hash function defined in Section 6.1 of [FIPS PUB 180-4] using message as the input message, M.

If the name member of normalizedAlgorithm is a cases-sensitive string match for "SHA-256":

Let result be the result of performing the SHA-256 hash function defined in Section 6.2 of [FIPS PUB 180-4] using message as the input message, M.

If the name member of normalizedAlgorithm is a cases-sensitive string match for "SHA-384":

Let result be the result of performing the SHA-384 hash function defined in Section 6.5 of [FIPS PUB 180-4] using message as the input message, M.

If the name member of normalizedAlgorithm is a cases-sensitive string match for "SHA-512":

Let result be the result of performing the SHA-1 hash function defined in Section 6.4 of [FIPS PUB 180-4] using message as the input message, M.
If performing the operation results in an error, then throw an OperationError.
Return a new ArrayBuffer containing result.

31. HKDF

31.1. Description

This section is non-normative.

The "HKDF" algorithm identifier is used to perform key derivation using the extraction-then-expansion approach described in [RFC 5869] and using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with HKDF. Such specifications must define the digest operation for the additional hash algorithms.

31.2. Registration

The recognized algorithm name for this algorithm is "HKDF".

Operation	Parameters	Result
deriveBits	HkdfParams	ArrayBuffer
importKey	None	CryptoKey
Get key length	None	null

31.3. HkdfParams dictionary

IDL


dictionary HkdfParams : Algorithm {
  // The algorithm to use with HMAC (e.g.: SHA-256)
  required HashAlgorithmIdentifier hash;
  // A bit string that corresponds to the salt used in the extract step.
  required BufferSource salt;
  // A bit string that corresponds to the context and application specific context for the derived keying material.
  required BufferSource info;
};

31.4. Operations

Derive Bits

If length is null, then throw an OperationError.
Let extractKey be a key equal to n zero bits where n is the size of the output of the hash function described by the hash member of normalizedAlgorithm.
Let keyDerivationKey be the secret represented by [[handle]] internal slot of key as the message.
Let result be the result of performing the HKDF extract and then the HKDF expand step described in Section 2 of [RFC 5869] using:
- the hash member of normalizedAlgorithm as Hash,
- keyDerivationKey as the input keying material, IKM,
- the contents of the salt member of normalizedAlgorithm as salt,
- the contents of the info member of normalizedAlgorithm as info,
- length as the value of L,
If the key derivation operation fails, then throw an OperationError.
Return result.

Import key

Let keyData be the key data to be imported.
If format is "raw":
1. If usages contains a value that is not "deriveKey" or "deriveBits", then throw a SyntaxError.
2. If extractable is not false, then throw a SyntaxError.
3. Let key be a new CryptoKey associated with the relevant global object of this [HTML], and representing the key data provided in keyData.
4. Set the [[type]] internal slot of key to "secret".
5. Set the [[extractable]] internal slot of key to false.
6. Let algorithm be a new KeyAlgorithm object.
7. Set the name attribute of algorithm to "HKDF".
8. Set the [[algorithm]] internal slot of key to algorithm.
9. Return key.
Otherwise:

throw a NotSupportedError.

Get key length

Return null.

32. PBKDF2

32.1. Description

This section is non-normative.

The "PBKDF2" algorithm identifier is used to perform key derivation using the PKCS#5 password-based key derivation function version 2.0, as defined in [RFC2898] using HMAC as the pseudo-random function, using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with PBKDF2. Such specifications must define the digest operation for the additional hash algorithms.

32.2. Registration

The recognized algorithm name for this algorithm is "PBKDF2".

Operation	Parameters	Result
deriveBits	Pbkdf2Params	ArrayBuffer
importKey	None	CryptoKey
Get key length	None	Integer or null

32.3. Pbkdf2Params dictionary

IDL


dictionary Pbkdf2Params : Algorithm {
  required BufferSource salt;
  [EnforceRange] required unsigned long iterations;
  required HashAlgorithmIdentifier hash;
};

32.4. Operations

Derive bits

If length is null or is not a multiple of 8, then throw an OperationError.
Let prf be the MAC Generation function described in Section 4 of [FIPS PUB 198-1] using the hash function described by the hash member of normalizedAlgorithm.
Let result be the result of performing the PBKDF2 operation defined in Section 5.2 of [RFC2898] using prf as the pseudo-random function, PRF, the password represented by [[handle]] internal slot of key as the password, P, the contents of the salt attribute of normalizedAlgorithm as the salt, S, the value of the iterations attribute of normalizedAlgorithm as the iteration count, c, and length divided by 8 as the intended key length, dkLen.
If the key derivation operation fails, then throw an OperationError.
Return result

Import key

If format is not "raw", throw a NotSupportedError
If usages contains a value that is not "deriveKey" or "deriveBits", then throw a SyntaxError.
If extractable is not false, then throw a SyntaxError.
Let key be a new CryptoKey associated with the relevant global object of this [HTML], and representing keyData.
Set the [[type]] internal slot of key to "secret".
Set the [[extractable]] internal slot of key to false.
Let algorithm be a new KeyAlgorithm object.
Set the name attribute of algorithm to "PBKDF2".
Set the [[algorithm]] internal slot of key to algorithm.
Return key.

Get key length

Return null.

33. JavaScript Example Code

33.1. Generate a signing key pair, sign some data

ECMAScript


var encoder = new TextEncoder('utf-8');

// Algorithm Object
var algorithmKeyGen = {
  name: "RSASSA-PKCS1-v1_5",
  // RsaHashedKeyGenParams
  modulusLength: 2048,
  publicExponent: new Uint8Array([0x01, 0x00, 0x01]),  // Equivalent to 65537
  hash: {
    name: "SHA-256"
  }
};

var algorithmSign = {
  name: "RSASSA-PKCS1-v1_5"
};

window.crypto.subtle.generateKey(algorithmKeyGen, false, ["sign"]).then(
  function(key) {
    var dataPart1 = encoder.encode("hello,");
    var dataPart2 = encoder.encode(" world!");

    return window.crypto.subtle.sign(algorithmSign, key.privateKey, [dataPart1, dataPart2]);
  },
  console.error.bind(console, "Unable to generate a key")
).then(
  console.log.bind(console, "The signature is: "),
  console.error.bind(console, "Unable to sign")
);

33.2. Symmetric Encryption

ECMAScript


var encoder = new TextEncoder('utf-8');
var clearDataArrayBufferView = encoder.encode("Plain Text Data");

var aesAlgorithmKeyGen = {
  name: "AES-CBC",
  // AesKeyGenParams
  length: 128
};

var aesAlgorithmEncrypt = {
  name: "AES-CBC",
  // AesCbcParams
  iv: window.crypto.getRandomValues(new Uint8Array(16))
};

// Create a key generator to produce a one-time-use AES key to encrypt some data
window.crypto.subtle.generateKey(aesAlgorithmKeyGen, false, ["encrypt"]).then(
  function(aesKey) {
    return window.crypto.subtle.encrypt(aesAlgorithmEncrypt, aesKey, [ clearDataArrayBufferView ]);
  }
).then(console.log.bind(console, "The ciphertext is: "),
       console.error.bind(console, "Unable to encrypt"));

34. IANA Considerations

34.1. JSON Web Signature and Encryption Algorithms Registration

This section registers the following algorithm identifiers in the IANA JSON Web Signature and Encryption Algorithms Registry for use with JSON Web Key. Note that the 'Implementation Requirements' field in the template refers to use with JSON Web Signature and JSON Web Encryption specifically, in which case use of unauthenticated encryption is prohibited.

Algorithm Name: "RS1"
Algorithm Description: RSASSA-PKCS1-v1_5 with SHA-1
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "RSA-OAEP-384"
Algorithm Description: RSA-OAEP using SHA-384 and MGF1 with SHA-384
Algorithm Usage Location(s): "alg"
JOSE Implementation Requirements: Optional+
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "RSA-OAEP-512"
Algorithm Description: RSA-OAEP using SHA-512 and MGF1 with SHA-512
Algorithm Usage Location(s): "alg"
JOSE Implementation Requirements: Optional+
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "A128CBC"
Algorithm Description: AES CBC using 128 bit key
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "A192CBC"
Algorithm Description: AES CBC using 192 bit key
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "A256CBC"
Algorithm Description: AES CBC using 256 bit key
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "A128CTR"
Algorithm Description: AES CTR using 128 bit key
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "A192CTR"
Algorithm Description: AES CTR using 192 bit key
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "A256CTR"
Algorithm Description: AES CTR using 256 bit key
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

Algorithm Name: "HS1"
Algorithm Description: HMAC using SHA-1
Algorithm Usage Location(s): "JWK"
JOSE Implementation Requirements: Prohibited
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

34.2. JSON Web Key Parameters Registration

Parameter Name: "ext"
Parameter Description: Extractable
Used with "kty" Value(s): *
Parameter Information Class: Public
Change Controller: W3C Web Cryptography Working Group
Specification Document(s): [[ This Document ]]

35. Acknowledgments

Thanks are due especially to Ryan Sleevi, the original author and editor of this document.

The editor would like to thank Adam Barth, Alex Russell, Ali Asad, Arun Ranganathan, Brian Smith, Brian Warner, Channy Yun, Charles Engelke, Eric Roman, Glenn Adams, Jim Schaad, Kai Engert, Michael Hutchinson, Michael B. Jones, Nick Van den Bleeken, Richard Barnes, Ryan Hurst, Tim Taubert, Vijay Bharadwaj, Virginie Galindo, and Wan-Teh Chang for their technical feedback and assistance.

Thanks to the W3C Web Cryptography WG, and to participants on the [email protected] mailing list.

The W3C would like to thank the Northrop Grumman Cybersecurity Research Consortium for supporting W3C/MIT.

The getRandomValues method in the Crypto interface was originally proposed by Adam Barth to the WHATWG.

36. References

36.1. Normative References

DOM4: W3C DOM4, A. Gregor, A. van Kesteren, Ms2ger, Alex Russell, Robin Berjon.
ECMA262: ECMAScript 5th Edition, A. Wirfs-Brock, P. Lakshman et al.
FIPS 180-4: FIPS PUB 180-4: Secure Hash Standard, NIST.
FIPS 198-1: The Keyed-Hash Message Authentication Code (HMAC) , July 2008, NIST.
HTML: HTML5.1, W3C.
ITU-T Recommendation X.690 (11/08): Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER) , ITU-T.
JSON Web Key: JSON Web Key , M. Jones, Microsoft.
JSON Web Algorithms: JSON Web Algorithms, M. Jones, Microsoft.
NIST SP 800-38A: NIST Special Publication 800-38A: Recommendation for Block Cipher Modes of Operation, Methods and Techniques, December 2001, NIST.
NIST SP 800-38B: NIST Special Publication 800-38B: Recommendation for Block Cipher Modes of Operation: The CMAC Mode for Authentication, May 2005, NIST.
NIST SP 800-38D: NIST Special Publication 800-38D: Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC, November 2007, NIST.
NIST SP 800-56A: NIST Special Publication 800-56A: Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised), March 2007, NIST.
NIST SP 800-56C: NIST Special Publication 800-56C: Recommendation for Key Derivation through Extraction-then-Expansion, November 2011, NIST.
RFC 2119: Key words for use in RFCs to Indicate Requirement Levels, S. Bradner. IETF.
RFC 2315: PKCS #7: Cryptographic Message Syntax, Version 1.5, B. Kaliski. RSA Laboratories.
RFC 2898: PKCS #5: Password-Based Cryptography Specification, Version 2.0, B. Kaliski. RSA Laboratories
RFC 3279: Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile, W. Polk, R. Housley, L. Bassham. IETF.
RFC3394: Advanced Encryption Standard (AES) Key Wrap Algorithm, J. Schaad, R. Housley, IETF.
RFC 3447: Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1, J. Jonsson, B. Kaliski. IETF.
RFC 5208: Public-Key Cryptography Standards (PKCS) #8: Private-Key Information Syntax Specification Version 1.2, B. Kaliski. IETF.
RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile, D. Cooper, S. Santesson, S. Farrell, S. Boeyen, R. Housley, W. Polk. IETF.
RFC 5480: Elliptic Curve Cryptography Subject Public Key Information, S. Turner, D. Brown, K. Yiu, R. Housley, T. Polk. IETF.
RFC 5869: HMAC-based Extract-and-Expand Key Derivation Function (HKDF)", H. Krawczyk, P. Eronen. IETF.
RFC 5915: Elliptic Curve Private Key Structure , S. Turner, D. Brown. IETF.
RFC6090: Fundamental Elliptic Curve Cryptography Algorithms, D. McGrew, K. Igoe, M.Salter. IETF.
SEC 1: SEC 1: Elliptic Curve Cryptography, Certicom Research
Web IDL Level 1: WebIDL Level 1, Yves Lafon, W3C, Travis Leithead, Cameron McCormack; Boris Zbarsky.
X9.62: ANS X9.62–2005: Public Key Cryptography for the Financial Services Industry, The Elliptic Curve Digital Signature Algorithm (ECDSA), ANSI.

36.2. Informative References

CDSA: Common Security: CDSA and CSSM, Version 2 (with corrigenda), the Open Group.
CNG: Cryptography API: Next Generation, Microsoft Corporation.
CryptoAPI: Cryptography Reference, Microsoft Corporation.
DRAFT-TLS-OBC: TLS Origin-Bound Certificates, D. Balfanz, D. Smetters, M. Upadhyay, A. Barth. IETF.
FileAPI: File API, A. Ranganathan, J. Sicking. W3C.
Indexed Database API: Indexed Database API, N. Mehta, J. Sicking, E. Graff, A. Popescu, J. Orlow, J. Bell. W3C.
PKCS11: PKCS #11: Cryptographic Token Interface Standard, RSA Laboratories.
RFC 4055: Additional Algorithms and Identifiers for RSA Cryptography for use in the Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile, J. Schaad, B. Kaliski, R. Housley. IETF.
RFC 5756: Updates for RSAES-OAEP and RSASSA-PSS Algorithm Parameters, S. Turner, D. Brown, K. Yiu, R. Housley, T. Polk. IETF.
RFC 5958: Asymmetric Key Packages, S. Turner. IETF.

JSON Web Key	AlgorithmIdentifier
ECMAScript `{ kty: "RSA", alg: "RS1" }`	ECMAScript `{ name: "RSASSA-PKCS1-v1_5", hash: { name: "SHA-1" } }`
ECMAScript `{ kty: "RSA", alg: "RS256" }`	ECMAScript `{ name: "RSASSA-PKCS1-v1_5", hash: { name: "SHA-256" } }`
ECMAScript `{ kty: "RSA", alg: "RS384" }`	ECMAScript `{ name: "RSASSA-PKCS1-v1_5", hash: { name: "SHA-384" } }`
ECMAScript `{ kty: "RSA", alg: "RS512" }`	ECMAScript `{ name: "RSASSA-PKCS1-v1_5", hash: { name: "SHA-512" } }`
ECMAScript `{ kty: "RSA", alg: "PS256" }`	ECMAScript `{ name: "RSA-PSS", hash: { name: "SHA-256" } }`
ECMAScript `{ kty: "RSA", alg: "PS384" }`	ECMAScript `{ name: "RSA-PSS", hash: { name: "SHA-384" } }`
ECMAScript `{ kty: "RSA", alg: "PS512" }`	ECMAScript `{ name: "RSA-PSS", hash: { name: "SHA-512" } }`
ECMAScript `{ kty: "RSA", alg: "RSA-OAEP" }`	ECMAScript `{ name: "RSA-OAEP", hash: { name: "SHA-1" } }`
ECMAScript `{ kty: "RSA", alg: "RSA-OAEP-256" }`	ECMAScript `{ name: "RSA-OAEP", hash: { name: "SHA-256" } }`
ECMAScript `{ kty: "RSA", alg: "RSA-OAEP-384" }`	ECMAScript `{ name: "RSA-OAEP", hash: { name: "SHA-384" } }`
ECMAScript `{ kty: "RSA", alg: "RSA-OAEP-512" }`	ECMAScript `{ name: "RSA-OAEP", hash: { name: "SHA-512" } }`
ECMAScript `{ kty: "EC", alg: "ES256" }`	ECMAScript `{ name: "ECDSA", namedCurve: "P-256" hash: { name: "SHA-256" } }`
ECMAScript `{ kty: "EC", alg: "ES384" }`	ECMAScript `{ name: "ECDSA", namedCurve: "P-384" hash: { name: "SHA-384" } }`
ECMAScript `{ kty: "EC", alg: "ES512" }`	ECMAScript `{ name: "ECDSA", namedCurve: "P-521" hash: { name: "SHA-512" } }`
ECMAScript `{ kty: "oct", alg: "A128CTR" }`	ECMAScript `{ name: "AES-CTR", length: 128 }`
ECMAScript `{ kty: "oct", alg: "A192CTR" }`	ECMAScript `{ name: "AES-CTR", length: 192 }`
ECMAScript `{ kty: "oct", alg: "A256CTR" }`	ECMAScript `{ name: "AES-CTR", length: 256 }`
ECMAScript `{ kty: "oct", alg: "A128CBC" }`	ECMAScript `{ name: "AES-CBC", length: 128 }`
ECMAScript `{ kty: "oct", alg: "A192CBC" }`	ECMAScript `{ name: "AES-CBC", length: 192 }`
ECMAScript `{ kty: "oct", alg: "A256CBC" }`	ECMAScript `{ name: "AES-CBC", length: 256 }`
ECMAScript `{ kty: "oct", alg: "A128KW" }`	ECMAScript `{ name: "AES-KW", length: 128 }`
ECMAScript `{ kty: "oct", alg: "A192KW" }`	ECMAScript `{ name: "AES-KW", length: 192 }`
ECMAScript `{ kty: "oct", alg: "A256KW" }`	ECMAScript `{ name: "AES-KW", length: 256 }`
ECMAScript `{ kty: "oct", alg: "A128GCM" }`	ECMAScript `{ name: "AES-GCM", length: 128 }`
ECMAScript `{ kty: "oct", alg: "A192GCM" }`	ECMAScript `{ name: "AES-GCM", length: 192 }`
ECMAScript `{ kty: "oct", alg: "A256GCM" }`	ECMAScript `{ name: "AES-GCM", length: 256 }`
ECMAScript `{ kty: "oct", alg: "A128GCMKW" }`	ECMAScript `{ name: "AES-GCM", length: 128 }`
ECMAScript `{ kty: "oct", alg: "A192GCMKW" }`	ECMAScript `{ name: "AES-GCM", length: 192 }`
ECMAScript `{ kty: "oct", alg: "A256GCMKW" }`	ECMAScript `{ name: "AES-GCM", length: 256 }`
ECMAScript `{ kty: "oct", alg: "HS1" }`	ECMAScript `{ name: "HMAC", hash: { name: "SHA-1" } }`
ECMAScript `{ kty: "oct", alg: "HS256" }`	ECMAScript `{ name: "HMAC", hash: { name: "SHA-256" } }`
ECMAScript `{ kty: "oct", alg: "HS384" }`	ECMAScript `{ name: "HMAC", hash: { name: "SHA-384" } }`
ECMAScript `{ kty: "oct", alg: "HS512" }`	ECMAScript `{ name: "HMAC", hash: "SHA-512" }`

Algorithm OID	subjectPublicKey ASN.1 structure	AlgorithmIdentifier	Reference
rsaEncryption (1.2.840.113549.1.1.1)	RSAPublicKey	`"RSASSA-PKCS1-v1_5"`, `"RSA-PSS"`, or `"RSA-OAEP"`	RFC 3279, RFC 4055, RFC 5756
id-RSASSA-PSS (1.2.840.113549.1.1.10)	RSAPublicKey	`"RSA-PSS"`	RFC 4055, RFC 5756
id-RSAES-OAEP (1.2.840.113549.1.1.7)	RSAPublicKey	`"RSA-OAEP"`	RFC 4055, RFC 5756
id-ecPublicKey (1.2.840.10045.2.1)	ECPoint	`"ECDH"` or `"ECDSA"`	RFC 5480
id-ecDH (1.3.132.1.12)	ECPoint	`"ECDH"`	RFC 5480
id-dsa (1.2.840.10040.4.1)	DSAPublicKey	`"DSA"`	RFC 3279

privateKeyAlgorithm	privateKey format	AlgorithmIdentifier	Reference
rsaEncryption (1.2.840.113549.1.1.1)	RSAPrivateKey	`"RSASSA-PKCS1-v1_5"`, `"RSA-PSS"`, or `"RSA-OAEP"`	RFC 3447, RFC 5958
id-RSASSA-PSS (1.2.840.113549.1.1.10)	RSAPrivateKey	`"RSA-PSS"`	RFC 3447, RFC 4055, RFC 5958
id-RSAES-OAEP (1.2.840.113549.1.1.7)	RSAPrivateKey	`"RSA-OAEP"`	RFC 3447, RFC 4055, RFC 5958
id-ecPublicKey (1.2.840.10045.2.1)	ECPrivateKey	`"ECDH"` or `"ECDSA"`	RFC 5480, RFC 5915, RFC 5958
id-ecDH (1.3.132.1.12)	ECPrivateKey	`"ECDH"`	RFC 5480, RFC 5915, RFC 5958
id-dsa (1.2.840.10040.4.1)	INTEGER	`"DSA"`	RFC 5958

Web Cryptography API

W3C Recommendation 26 January 2017

Abstract

Status of this Document

1. Introduction

2. Use Cases

2.1. Multi-factor Authentication

2.2. Protected Document Exchange

2.3. Cloud Storage

2.4. Document Signing

2.5. Data Integrity Protection

2.6. Secure Messaging

2.7. JavaScript Object Signing and Encryption (JOSE)

3. Conformance

3.1. Extensibility

4. Scope

4.1. Level of abstraction

4.2. Cryptographic algorithms

4.3. Out of scope

5. Concepts

5.1. Underlying Cryptographic Implementation

5.2. Key Storage

6. Security considerations

6.1. Security considerations for implementers

6.2. Security considerations for authors

6.3. Security considerations for users

7. Privacy considerations

8. Dependencies

9. Terminology

10. Crypto interface

10.1. Description

10.2. Methods and Parameters

10.2.1. The getRandomValues method

10.3. Attributes

10.3.1. The subtle attribute

11. Algorithm dictionary

11.1. Algorithm Dictionary Members

12. KeyAlgorithm dictionary

12.1. Description

12.2. KeyAlgorithm dictionary members

13. CryptoKey interface

13.1. Description

13.2. Key interface data types

13.3. CryptoKey internal slots

13.4. CryptoKey interface members

13.5. Structured clone algorithm

14. SubtleCrypto interface

14.1. Description

14.2. Data Types

14.3. Methods and Parameters

14.3.1. The encrypt method

14.3.2. The decrypt method

14.3.3. The sign method

14.3.4. The verify method

14.3.5. The digest method

14.3.6. The generateKey method

14.3.7. The deriveKey method

14.3.8. The deriveBits method

14.3.9. The importKey method

14.3.10. The exportKey method

14.3.11. The wrapKey method

14.3.12. The unwrapKey method

14.4. Exceptions

15. JsonWebKey dictionary

Description

16. BigInteger

17. CryptoKeyPair dictionary

18. Algorithms

18.1. Overview

18.2. Concepts

18.2.1. Naming

18.2.2. Supported Operations

18.2.3. Normalization

18.3. Specification Conventions

18.4. Algorithm Normalization

18.4.1. Description

18.4.2. Internal State Objects

18.4.3. Defining an Algorithm

18.4.4. Normalizing an algorithm

18.5. Recommendations