cjdns

cjdns implements an encrypted IPv6 network using public-key cryptography for address allocation and a distributed hash table (DHT) for routing. The result is near-zero-configuration networking that sidesteps many of the security and scalability problems baked into the conventional internet. For sovereign builders, cjdns is appealing because there is no hierarchy, no edge routing, and no authority assigning who gets which address — every node is equal.

Key-derived addresses

A node's IPv6 address lives inside the fc00::/8 unique-local space and is computed from the SHA-512 hash of the SHA-512 hash of its public key. Because the address is the identity, you cannot impersonate another node or have your address handed out by anyone else. Traffic through cjdns is carried in an encrypted tunnel keyed to a node's keypair, providing forward secrecy across the path.

DHT routing

cjdns stores its routing table in a distributed hash table similar to Kademlia. A packet is handed to a router, which labels it with directions toward the router best positioned to handle it — one that is physically near and numerically close to the destination address. This avoids the global routing tables and centralized coordination that make traditional networks fragile and censorable, and it lets a cjdns mesh self-organize as nodes come and go.

cjdns shares its key-as-address philosophy with the Yggdrasil Network, and like Reticulum it is part of the toolkit for building infrastructure that does not depend on permissioned providers.