
Decentralized P2P Networks

Anonymous P2P networks without a central authority.
dn42 is a big dynamic VPN, which employs Internet technologies (BGP, whois database, DNS, etc). Participants connect to each other using network tunnels (GRE, OpenVPN, Tinc, IPsec) and exchange routes thanks to the Border Gateway Protocol...
dn42 can be used to learn networking and to connect private networks, such as hackerspaces or community networks. But above all, experimenting with routing in dn42 is fun!
In early 2005, a few people fed up with the way the Internet was heading, began in earnest to create a large wide area network that was secure and lived in its own space. On this new network anyone would be free to do as they saw fit - roam about, host services, or just be social without fear of being monitored or even worse censored. The first step to bring this network to fruition was to encrypt the information that normally travels across the Internet. What they ended up with is known as anoNet.
IPFS is a global, versioned, peer-to-peer filesystem. It combines ideas from Git, BitTorrent, Kademlia, SFS, and the web. It is like a single bittorrent swarm, exchanging git objects. IPFS provides an interface as simple as the HTTP web, but with permanence built in. You can also mount the world at /ipfs. IPFS could become a new major subsystem of the internet. If built right, it could complement or replace HTTP. It offers two approaches: content-addressing (ipfs://) and uploader-addressing (ipns://) allowing for mutable sites.
WASTE is a peer-to-peer and friend-to-friend protocol and software application that features instant messaging, chat rooms and file browsing/sharing capabilities.
WASTE is a decentralized chat, instant messaging and file sharing program and protocol. It behaves similarly to a virtual private network by connecting to a group of trusted computers, as determined by the users. This kind of network is commonly referred to as a darknet. It uses strong encryption to ensure that third parties cannot decipher the messages being transferred. The same encryption is used to transmit and receive instant messages, chat, and files, maintain the connection, and browse and search.
GNUnet is a framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services. A first service implemented on top of the networking layer allows anonymous censorship-resistant file-sharing. Anonymity is provided by making messages originating from a peer indistinguishable from messages that the peer is routing. All peers act as routers and use link-encrypted connections with stable bandwidth utilization to communicate with each other. GNUnet uses a simple, excess-based economic model to allocate resources. Peers in GNUnet monitor each others behavior with respect to resource usage; peers that contribute to the network are rewarded with better service.
RetroShare is a open source cross-platform, private and secure decentralized communication system. It lets you to securely chat, share photos, videos, and more, using OpenPGP to authenticate peers and OpenSSL to encrypt all communication.
RetroShare features:
Chat
Send text and images. Discuss with various people in chat rooms. Express your emotions with the rich smiley set. Use distant chat to securely chat with friends-of-friends.
Voice and Video
Make free and secure calls with the VoIP plugin. Catch up face to face with a video call.
Mail
Send encrypted messages to other members of the network. Retroshare can store encrypted messages on friends nodes to deliver messages while you're offline.
File sharing
Share files with your friends or with the whole network. Use the search to find files. Retroshare uses swarming similar to BitTorrent, to accelerate the download. This makes it possible to share big files with 1GB or more. Your privacy is protected with anonymous tunnels. Only your direct friends might learn which files you download.
Forums
You can read and write forum posts offline. This is perfect while you're on the go. When you have an Internet connection, Retroshare will automatically sync forums with your friends. Decentralized forums are censorship resistant by design.
Posted
Share your favorite links. See which links others like. Vote and discuss links.
Channels
Publish files in channels. Subscribe to channels and automatically download the latest files. Comment on files and spread them to your friends.
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.
Many applications are available that interface with I2P, including mail, peer-peer, IRC chat and others.
Alternative i2p Clients: https://geti2p.net/en/about/alternative-clients
The main I2P client implementation uses Java. If for some reason you can't use Java on your device, there are alternative implementations developed by community members.
i2pd i2pd is a I2P client implementation in C++. As of early 2016, i2pd is became stable enough to be used in production, and since summer 2016 it fully implements all I2P APIs.
Kovri Kovri is active i2pd fork developed for Monero cryptocurrency.
Go-I2P Go-I2P is I2P client developed using the Go programming language. The project is in early development.
Hypercore Protocol is a peer-to-peer data network built on the Hypercore logs. Hypercores are signed, append-only logs. They're like lightweight blockchains without the consensus algorithm. As with BitTorrent, as more people "seed" a dataset it will increase the available bandwidth.
ZeroNet uses cryptography (Bitcoin library) and BitTorrent DHT (centralized trackers) to build a distributed censorship-resistant network.
Users can publish static or dynamic sites/applications into ZeroNet and visitors can choose to also serve the application/site. Sites /applications will remain on-line even if it is being served by only 1 peer.
When a site/app is updated by its owner, all nodes (including previous visitors) serving that site/app, will receive only the incremental updates done to the site content (and in real time).
Zeronet counts with a built-in SQLite database. This makes content-heavy site development easy. The database is also synced with hosting nodes with incremental updates.
It is based on Python and JavaScript.