GNUnet is a free software framework for decentralized, peer-to-peer networking and an official GNU package. The framework offers link encryption, peer discovery, resource allocation, communication over many transports (such as tcp, udp, http, https, wlan and bluetooth) and various basic peer-to-peer algorithms for routing, multicast and network size estimation.

The primary application at this point is anonymous, censorship-resistant file-sharing, allowing users to anonymously publish or retrieve information of all kinds. GNUnet uses GNU libextractor to automatically annotate shared files with metadata.

The file sharing service uses GNUnet's anonymity protocol for routing queries and replies. Forwarded query messages are used to search for content and blocks of data. Depending on load of the forwarding node, messages are forwarded to zero or more nodes. When a node is under stress it drops requests from its neighbor nodes having lower internal trust value. A special feature of GNUnet's anonymity protocol is that the user can select an individual anonymity level. The anonymity level determines how much cover traffic a peer must have to hide the user's own traffic. Users can specify an anonymity level for each publish, search and download operation. An anonymity level of zero can be used to select non-anonymous file-sharing. GNUnet's DHT infrastructure is only used if non-anonymous file-sharing is specified.

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About GNUnet

GNUnet is a framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services. Our high-level goal is to provide a strong free software foundation for a global network that provides security and in particular respects privacy.

GNUnet started with an idea for anonymous censorship-resistant file-sharing, but has grown to incorporate other applications as well as many generic building blocks for secure networking applications. In particular, GNUnet now includes the GNU Name System, a privacy-preserving, decentralized public key infrastructure.

The foremost goal of the GNUnet project is to become a widely used, reliable, open, non-discriminating, egalitarian, unfettered and censorship-resistant system of free information exchange. We value free speech above state secrets, law-enforcement or intellectual property. GNUnet is supposed to be an anarchistic network, where the only limitation for peers is that they must contribute enough back to the network such that their resource consumption does not have a significant impact on other users. GNUnet should be more than just another file-sharing network. The plan is to offer many other services and in particular to serve as a development platform for the next generation of decentralized Internet protocols.