Pull requests VERY welcome!

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AnoNet is a decentralized friend-to-friend network built using VPNs and software BGP routers. anoNet works by making it difficult to learn the identities of others on the network allowing them to anonymously host IPv4 and IPv6 services)

BitPhone is a mobile communications device with the features of a modern smartphone built on top of decentralized BitCoin-style proof-of-work networking.

BitMessage is a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities. See whitepaper

Books are a stable, production tested communication protocol suitable for a wide range of information services.

buddycloud is a set of tools, open source software and protocols to help you build a distributed social network. All the code is on GitHub.

Camlistore is your personal storage system for life. It is an acronym for "Content-Addressable Multi-Layer Indexed Storage" and could be described as "Like git for all content in your life"

Commotion Wireless is an open-source communication tool that uses mobile phones, computers, and other wireless devices to create decentralized mesh networks.

The Cryptosphere is a global peer-to-peer cryptosystem for publishing and securely distributing both data and HTML5/JS applications pseudonymously with no central point of failure. It's built on top of the next-generation Networking and Cryptography (NaCl) library and the Git data model. Code

CryptAByte CryptAByte.com is a free online drop box that enables secure (encrypted) message and file sharing over the web using a public-key infrastructure. Messages and files are encrypted using a public key and can only be decrypted using the passphrase entered when your key is created. Your data is never stored in plaintext, and is impossible to decrypt without your passphrase.

Diaspora* is a free social network consisting of personal web server that implements a distributed social networking service. Diaspora* is a fun and creative community that puts you in control.

DeadC Create a one-click expiring link

The Drogulus (WIP) is a programmable peer-to-peer data store. It's an open, federated and decentralised system where the identity of users and provenance of data is ensured by cryptographically signing digital assets. Redecentralise Video interview

eDonkey network is a decentralized, mostly server-based, peer-to-peer file sharing network best suited to share big files among users, and to provide long term availability of files

Firecloud is a P2P web publishing platform in your using Persona and WebRTC to work its magic.

Freedom Box is about privacy, control, ease of use and dehierarchicalization. Inspired by Eben Moglen's vision of a small, cheap and simple computer that serves freedom in the home. We are building a Debian based platform for distributed applications.

Freenet is free software which lets you anonymously share files, browse and publish "freesites" (web sites accessible only through Freenet) and chat on forums, without fear of censorship. Freenet is decentralised to make it less vulnerable to attack, and if used in "darknet" mode, where users only connect to their friends, is very difficult to detect.

Freifunk is a non-commercial initiative for free decentraliced wireless mesh networks. Technically Freifunk firmwares are based on OpenWRT and OLSR or B.A.T.M.A.N.

GNUnet is GNU's framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services.

Grimwire is a browser OS which uses Web Workers for process isolation, and WebRTC for peer-to-peer communication.

Guifi is a european (especially spanish) large network with over 22000 active nodes. Uses wifi in both infrastructure and mesh mode. Over 25km of fiber as well so far.

I2P is an anonymizing network, offering a simple layer that identity-sensitive applications can use to securely communicate. All data is wrapped with several layers of encryption, and the network is both distributed and dynamic, with no trusted parties.

Kademlia is a distributed hash table for decentralized peer-to-peer computer networks

Kune is based on Apache Wave and is a free/open source distributed social network focused on collaboration rather than just on communication.[2] That is, it focuses on online real-time collaborative editing, decentralized social networking and web publishing, while focusing on workgroups rather than just on individuals.

LibreVPN is a virtual mesh network using tinc plus configuration scripts that even let you build your own mesh VPN. It's also IPv6 enabled.

Mixmaster is a remailer network. It represents the second generation of remailers. Mixmaster can be used via a web sites like Anonymouse or as a stand-alone client.

Mixminion is a new remailer approach. The so-called type III remailer allows it to receive and send anonymous messages. However the development has stalled and the current software needs improvement.

Movim is a decentralized open source social network based on XMPP.

NameCoin is a decentralized naming system based on Bitcoin technology.

Nightweb connects your Android device or PC to an anonymous, peer-to-peer social network. You can write posts and share photos, and your followers will retrieve them using BitTorrent running over the I2P anonymous network. It is still experimental.

1TY is "One Time Self Destructing Links For Sharing Sensitive Information"

OpenNIC Project is an alternative DNS provider that is open and democratic.

Osiris is software for decentralized portal, managed and shared via P2P between members.

P is a small JavaScript library for creating peer-to-peer applications in browsers. It allows for transitive connections across peers which makes certain network topologies, such mesh networks, easy to establish.

PeerCDN automatically serves a site's static resources (images, videos, and file downloads) over a peer-to-peer network made up of the visitors currently on the site.

PeerServer is a peer-to-peer client server using WebRTC, where your browser acts as a server for other browsers across WebRTC peer-to-peer data channels.

Phantom is (was?) a system for generic, decentralized, unstoppable internet anonymity

Project Byzantium - Ad-hoc wireless mesh networking for the zombie apocalypse. The goal of Project Byzantium is to develop a communication system by which users can connect to each other and share information in the absence of convenient access to the Internet. This is done by setting up an ad-hoc wireless mesh network that offers services which replace popular websites often used for this purpose, such as Twitter and IRC.

Project Meshnet aims to build a sustainable decentralized alternative internet. Used by Hyperboria and built on CJDNS.

pubsubhubbub is a simple, open, server-to-server webhook-based pubsub (publish/subscribe) protocol for any web accessible resources.

pump;io Described as "a stream server that does most of what people really want from a social network". It's a social stream with support for federated comunication.

qaul.net implements a redundant, open communication principle, in which wireless-enabled computers and mobile devices can directly form a spontaneous network. Chat functions, file sharing and voice chat is possible independent of internet and cellular networks.

Quick mesh project is an openwrt based mesh networking firmware. Can be installed on any openwrt supported system. Auto configures any needed connections, auto detects internet connections and aunounces them. Native IPv6 support with IPv4 tunnels for current networking support.

RetroShare is an open source, decentralised communication platform. It lets you chat and share with friends and family, with a web-of-trust to authenticate peers.

The Serval Project lets mobile phones make phone calls to each other peer-to-peer without a base station.

Sneer is a free and open source sovereign computing platform. It runs on your Windows, Mac or Linux machine (like Skype or Firefox) using the Java VM. It enables you to create your personal cluster by sharing hardware resources (CPU, disk space, network bandwidth) with your friends, host your own social network, information and media, create sovereign applications and share them with others, download and run sovereign applications created by others. You can do all these things directly with your peers, in an autonomous, sovereign way, without depending on online service providers such as email providers, Google, Facebook, etc.

Syndie is an open source system for operating distributed forums offering a secure and consistent interface to various anonymous and non-anonymous content networks.

StatusNet is an open source microblogging platform that supports federation.

Tahoe-LAFS is a Free and Open cloud storage system. It distributes your data across multiple servers. Even if some of the servers fail or are taken over by an attacker, the entire filesystem continues to function correctly, preserving your privacy and security.

Tavern is a distributed, anonymous, unblockable network designed to ensure that no one is silenced, censored, or cut off from the rest of the world

Telehash a new encrypted P2P JSON-based protocol enabling developers to quickly build apps that are distributed and private (see v2 of the spec)

Tent is a protocol that puts users back in control. Users should control the data they create, choose who can access it, and change service providers without losing their social graph. Tent is a protocol, not a platform. Like email, anyone can build Tent apps or host Tent servers, all Tent servers can talk to each other, and there is no central authority to restrict users or developers.

The FNF is the free network foundation: teaching how to build wireless community networks.

Tidepools is being developed within the Red Hook Mesh Network, for addressing local, social incentives for mesh use. An Open Source, Collaborative, Mobile Mapping & Social Hub, Reflecting Community Needs & Culture through Custom Apps, Time-based Maps, & Data Feeds.

Tonika is a (digital) social network, which (by design) restricts direct communication to pairs of users who are friends, possesses many of the security properties (privacy, anonymity, deniability, resilience to denial-of-service attacks, etc.) that human sociaties implement organically in daily life.

Tor protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location.

Tox The goal of this project is to create a configuration free p2p skype replacement.

Tribler Aims to create a censorship-free Internet. Already deployed, used and incrementally improved for 8-years. Tribler uses an upcoming IETF Internet Standard for video streaming and is backward compatible with Bittorrent. Future aim is using smartphones to even bypass Internet kill switches. An early proof-of-principle Tribler-mobile is available on the Android Market. Key principle: 'the only way to take it down is to take The Internet down'. Overview paper.

TrueCrypt Free open source disk encryption software for Windows 7/Vista/XP/Mac OSX/ & Linux. Creates a virtual encrypted disk within a file and mounts it as a real disk. Encrypts an entire partition or storage device such as USB flash drive or hard drive. Encrypts a partition or drive where Windows is installed (pre-boot authentication). Encryption is automatic, real-time (on-the-fly) and transparent. Parallelization and pipelining allow data to be read and written as fast as if the drive was not encrypted. Encryption can be hardware-accelerated on modern processors. Provides plausible deniability, in case an adversary forces you to reveal the password: Hidden volume (steganography) and hidden operating system. More information on documentation page

Unhosted - also known as "serverless", "client-side", or "static" web apps, unhosted web apps do not send your user data to their server. Either you connect your own server at runtime, or your data stays within the browser.

Vole is a web-based social network that you use in your browser, without a central server. It's built on the power of Bittorrent, Go and Ember.js. Uses bittorrent sync.

Webfist is a fallback for when providers don't support WebFinger natively. It lets you do WebFinger lookups for email addresses even if the owner of the domain name isn't playing along. WebFist works because of a judo move on an existing infrastructure: DKIM.

Wave is a distributed, near-real-time, rich collaboration platform that allows users to work together in new and exciting ways. Wave allows for flexible modes of communication, blending chat, email and collaborative document editing in to one seamless environment.

YACY is a peer-to-peer search that anyone can use to build a search portal for their intranet or to help search the public internet. When contributing to the world-wide peer network, the scale of YaCy is limited only by the number of users in the world and can index billions of web pages. It is fully decentralized, all users of the search engine network are equal, the network does not store user search requests and it is not possible for anyone to censor the content of the shared index.

ZeroTier One is an open source application that creates huge distributed Ethernet networks. It makes use of supernodes, but these run the same code as ordinary nodes and end-to-end encryption protects all unicast traffic. Semi-commercial with a freemium model.

Zero Bin is an open source alternative for pastebin with burn-after-read function & client side encryption. Source code is also available on github https://github.com/sametmax/0bin

BitCoin is a digital currency, a protocol, and a software that enables it. Decentralized crypto-currency

LiteCoin is a peer-to-peer Internet currency that enables instant payments to anyone in the world (was based on Bitcoin)

PeerCoin/PPCoin is the first known cryptocurrency based on an implementation of a combined proof-of-stake/proof-of-work system

See bitcointalk for a list of others.