'); msg.document.write(footnote); msg.document.write('<\/p>

'); msg.document.write(''); msg.document.write('<\/fieldset><\/form><\/div><\/body><\/html>'); msg.document.close(); setTimeout(function() { var height = msg.document.getElementById('footnote').offsetHeight; msg.resizeTo(598, height + 100); } , 100); msg.focus(); }

13 Configuring Oracle Database Network Encryption and Data Integrity

You can configure native Oracle Net Services data encryption and integrity for both servers and clients.

Topics:

About Oracle Database Network Encryption and Data Integrity

Oracle Database enables you to encrypt data that is sent over a network.

Topics:

About Oracle Data Network Encryption and Integrity

Oracle Database provides data network encryption and integrity to ensure that data is secure as it travels across the network.

The purpose of a secure cryptosystem is to convert plaintext data into unintelligible ciphertext based on a key, in such a way that it is very hard (computationally infeasible) to convert ciphertext back into its corresponding plaintext without knowledge of the correct key.

In a symmetric cryptosystem, the same key is used both for encryption and decryption of the same data. Oracle Database provides the Advanced Encryption Standard (AES) symmetric cryptosystem for protecting the confidentiality of Oracle Net Services traffic.

Advanced Encryption Standard

Oracle Database supports the Federal Information Processing Standard (FIPS) encryption algorithm, Advanced Encryption Standard (AES).

AES can be used by all U.S. government organizations and businesses to protect sensitive data over a network. This encryption algorithm defines three standard key lengths, which are 128-bit, 192-bit, and 256-bit. All versions operate in outer Cipher Block Chaining (CBC) mode.

Oracle Database Network Encryption Data Integrity

Encrypting network data provides data privacy so that unauthorized parties cannot view plaintext data as it passes over the network.

Oracle Database also provides protection against two forms of active attacks.

Table 13-1 provides information about these attacks.

Table 13-1 Two Forms of Network Attacks

Type of Attack Explanation

Data modification attack

An unauthorized party intercepting data in transit, altering it, and retransmitting it is a data modification attack. For example, intercepting a $100 bank deposit, changing the amount to $10,000, and retransmitting the higher amount is a data modification attack.

Replay attack

Repetitively retransmitting an entire set of valid data is a replay attack, such as intercepting a $100 bank withdrawal and retransmitting it ten times, thereby receiving $1,000.

Data Integrity Algorithms Support

A keyed, sequenced implementation of the Message Digest 5 (MD5) algorithm or the Secure Hash Algorithm (SHA-1 and SHA-2) protect against these attacks.

Both of these hash algorithms create a checksum that changes if the data is altered in any way. This protection operates independently from the encryption process so you can enable data integrity with or without enabling encryption.

See Also:

Diffie-Hellman Based Key Negotiation

You can use the Diffie-Hellman key negotiation algorithm to secure data in a multiuser environment.

Secure key distribution is difficult in a multiuser environment. Oracle Database uses the well known to perform secure key distribution for both encryption and data integrity.

When encryption is used to protect the security of encrypted data, keys must be changed frequently to minimize the effects of a compromised key. Accordingly, the Oracle Database key management function changes the session key with every session.

You can use Authentication Key Fold-in to defeat a possible third-party attack (historically called the man-in-the-middle attack) on the Diffie-Hellman key negotiation algorithm key negotiation. It strengthens the session key significantly by combining a shared secret, known only to the client and the server, with the original session key negotiated by Diffie-Hellman.

The client and the server begin communicating using the session key generated by Diffie-Hellman. When the client authenticates to the server, they establish a shared secret that is only known to both parties. Oracle Database combines the shared secret and the Diffie-Hellman session key to generate a stronger session key designed to defeat a man-in-the-middle attack.

Note:

The authentication key fold-in function is an imbedded feature of Oracle Database and requires no configuration by the system or network administrator.

Configuration of Data Encryption and Integrity

You can configure Oracle Database native Oracle Net Services encryption and integrity and presumes the prior installation of Oracle Net Services.

Topics:

About Activating Encryption and Integrity

In any network connection, both the client and server can support multiple encryption algorithms and integrity algorithms.

When a connection is made, the server selects which algorithm to use, if any, from those algorithms specified in the sqlnet.ora files.The server searches for a match between the algorithms available on both the client and the server, and picks the first algorithm in its own list that also appears in the client list. If one side of the connection does not specify an algorithm list, all the algorithms installed on that side are acceptable. The connection fails with error message ORA-12650 if either side specifies an algorithm that is not installed.

Encryption and integrity parameters are defined by modifying a sqlnet.ora file on the clients and the servers on the network.

You can choose to configure any or all of the available encryption algorithms, and either or both of the available integrity algorithms. Only one encryption algorithm and one integrity algorithm are used for each connect session.

Note:

Oracle Database selects the first encryption algorithm and the first integrity algorithm enabled on the client and the server. Oracle recommends that you select algorithms and key lengths in the order in which you prefer negotiation, choosing the strongest key length first.

See Also:

About Negotiating Encryption and Integrity

The profile on client and server systems using data encryption and integrity (sqlnet.ora file) must contain some or all of the REJECTED, ACCEPTED, REQUESTED, and REQUIRED parameters.

Topics:

About the Values for Negotiating Encryption and Integrity

Oracle Net Manager can be used to specify four possible values for the encryption and integrity configuration parameters.

The following four values are listed in the order of increasing security, and they must be used in the profile file (sqlnet.ora) for the client and server of the systems that are using encryption and integrity.

The value REJECTED provides the minimum amount of security between client and server communications, and the value REQUIRED provides the maximum amount of network security:

  • REJECTED

  • ACCEPTED

  • REQUESTED

  • REQUIRED

The default value for each of the parameters is ACCEPTED.

Oracle Database servers and clients are set to ACCEPT encrypted connections out of the box. This means that you can enable the desired encryption and integrity settings for a connection pair by configuring just one side of the connection, server-side or client-side.

So, for example, if there are many Oracle clients connecting to an Oracle database, you can configure the required encryption and integrity settings for all these connections by making the appropriate sqlnet.ora changes at the server end. You do not need to implement configuration changes for each client separately.

Table 13-2 shows whether the security service is enabled, based on a combination of client and server configuration parameters. If either the server or client has specified REQUIRED, the lack of a common algorithm causes the connection to fail. Otherwise, if the service is enabled, lack of a common service algorithm results in the service being disabled.

Table 13-2 Encryption and Data Integrity Negotiations

Client Setting Server Setting Encryption and Data Negotiation

REJECTED

REJECTED

OFF

ACCEPTED

REJECTED

OFF

REQUESTED

REJECTED

OFF

REQUIRED

REJECTED

Connection fails

REJECTED

ACCEPTED

OFF

ACCEPTED

ACCEPTED

OFFFoot 1

REQUESTED

ACCEPTED

ON

REQUIRED

ACCEPTED

ON

REJECTED

REQUESTED

OFF

ACCEPTED

REQUESTED

ON

REQUESTED

REQUESTED

ON

REQUIRED

REQUESTED

ON

REJECTED

REQUIRED

Connection fails

ACCEPTED

REQUIRED

ON

REQUESTED

REQUIRED

ON

REQUIRED

REQUIRED

ON

Footnote 1

This value defaults to OFF. Cryptography and data integrity are not enabled until the user changes this parameter by using Oracle Net Manager or by modifying the sqlnet.ora file.

REJECTED Configuration Parameter

The REJECTED value disables the security service, even if the other side requires this service.

In this scenario, this side of the connection specifies that the security service is not permitted. If the other side is set to REQUIRED, the connection terminates with error message ORA-12650. If the other side is set to REQUESTED, ACCEPTED, or REJECTED, the connection continues without error and without the security service enabled.

ACCEPTED Configuration Parameter

The ACCEPTED value enables the security service if the other side requires or requests the service.

In this scenario, this side of the connection does not require the security service, but it is enabled if the other side is set to REQUIRED or REQUESTED. If the other side is set to REQUIRED or REQUESTED, and an encryption or integrity algorithm match is found, the connection continues without error and with the security service enabled. If the other side is set to REQUIRED and no algorithm match is found, the connection terminates with error message ORA-12650.

If the other side is set to REQUESTED and no algorithm match is found, or if the other side is set to ACCEPTED or REJECTED, the connection continues without error and without the security service enabled.

REQUESTED Configuration Parameter

The REQUESTED value enables the security service if the other side permits this service.

In this scenario, this side of the connection specifies that the security service is desired but not required. The security service is enabled if the other side specifies ACCEPTED, REQUESTED, or REQUIRED. There must be a matching algorithm available on the other side, otherwise the service is not enabled. If the other side specifies REQUIRED and there is no matching algorithm, the connection fails.

REQUIRED Configuration Parameter

The REQUIRED value enables the security service or preclude the connection.

In this scenario, this side of the connection specifies that the security service must be enabled. The connection fails if the other side specifies REJECTED or if there is no compatible algorithm on the other side.

Configuring Encryption and Integrity Parameters Using Oracle Net Manager

You can set up or change encryption and integrity parameter settings using Oracle Net Manager.

Topics:

Configuring Encryption on the Client and the Server

Use Oracle Net Manager to configure encryption on the client and on the server.

  1. Start Oracle Net Manager.

    • (UNIX) From $ORACLE_HOME/bin, enter the following command at the command line:

      netmgr

    • (Windows) Select Start, Programs, Oracle - HOME_NAME, Configuration and Migration Tools, then Net Manager.

  2. Expand Oracle Net Configuration, and from Local, select Profile.
  3. From the Naming list, select Network Security.

    The Network Security tabbed window appears.

  4. Select the Encryption tab.
  5. Select CLIENT or SERVER option from the Encryption box.
  6. From the Encryption Type list, select one of the following:

    • REQUESTED

    • REQUIRED

    • ACCEPTED

    • REJECTED

  7. (Optional) In the Encryption Seed field, enter between 10 and 70 random characters. The encryption seed for the client should not be the same as that for the server.
  8. Select an encryption algorithm in the Available Methods list. Move it to the Selected Methods list by choosing the right arrow (>). Repeat for each additional method you want to use.
  9. Select File, Save Network Configuration. The sqlnet.ora file is updated.
  10. Repeat this procedure to configure encryption on the other system. The sqlnet.ora file on the two systems should contain the following entries:

    • On the server:

      SQLNET.ENCRYPTION_SERVER = [accepted | rejected | requested | required]
SQLNET.ENCRYPTION_TYPES_SERVER = (valid_encryption_algorithm [,valid_encryption_algorithm])
    

      

    • 

      On the client:
      

      SQLNET.ENCRYPTION_CLIENT = [accepted | rejected | requested | required]
SQLNET.ENCRYPTION_TYPES_CLIENT = (valid_encryption_algorithm [,valid_encryption_algorithm])

      • 

    

    

    11. 





Table 13-3 lists valid encryption algorithms and their associated legal values.




Table 13-3 Valid Encryption Algorithms






Algorithm Name
Legal Value








AES 256-bit key




AES256








AES 192-bit key




AES192








AES 128-bit key




AES128



















Configuring Integrity on the Client and the Server




You can use Oracle Net Manager to configure network integrity on both the client and the server.


    

  1. Start Oracle Net Manager.

    

      

    • 

      (UNIX) From $ORACLE_HOME/bin, enter the following command at the command line:
      

      netmgr

      • 

    • 

      (Windows) Select Start, Programs, Oracle - HOME_NAME, Configuration and Migration Tools, then Net Manager.
      

      • 

    

    

    2. 

  2. Expand Oracle Net Configuration, and from Local, select Profile.
    3. 

  3. From the Naming list, select Network Security.

    

    The Network Security tabbed window appears.
    

    

    4. 

  4. Select the Integrity tab.


    5. 

  5. Depending upon which system you are configuring, select the Server or Client from the Integrity box.
    6. 

  6. From the Checksum Level list, select one of the following checksum level values:

    

      

    • 

      REQUESTED
      

      • 

    • 

      REQUIRED
      

      • 

    • 

      ACCEPTED
      

      • 

    • 

      REJECTED
      

      • 

    

    

    7. 

  7. Select an integrity algorithm in the Available Methods list. Move it to the Selected Methods list by choosing the right arrow (>). Repeat for each additional method you want to use.
    8. 

  8. Select File, Save Network Configuration.

    

    The sqlnet.ora file is updated.
    

    

    9. 

  9. Repeat this procedure to configure integrity on the other system.

    

    The sqlnet.ora file on the two systems should contain the following entries:
    

      

    • 

      On the server:
      

      SQLNET.CRYPTO_CHECKSUM_SERVER = [accepted | rejected | requested | required]
SQLNET.CRYPTO_CHECKSUM_TYPES_SERVER = (valid_crypto_checksum_algorithm [,valid_crypto_checksum_algorithm])

      • 

    • 

      On the client:
      

      SQLNET.CRYPTO_CHECKSUM_CLIENT = [accepted | rejected | requested | required]
SQLNET.CRYPTO_CHECKSUM_TYPES_CLIENT = (valid_crypto_checksum_algorithm [,valid_crypto_checksum_algorithm])

      • 

    

    

    10. 





Table 13-4 lists valid integrity algorithms and their associated legal values.




Table 13-4 Valid Integrity Algorithms






Algorithm Name
Legal Values








MD5




MD5








SHA-1




SHA1








SHA-2




SHA256








SHA-2




SHA384








SHA-2




SHA512