Bitcoin Core Considers Ditching Low-Usage CJDNS Support

Bitcoin Core developers are weighing whether to keep support for CJDNS, an encrypted peer-to-peer routing protocol, after automated network checks revealed only seven 'good' nodes. The low adoption metrics have forced contributors to re-examine the practical security and engineering trade-offs of maintaining legacy overlay networks inside the main Bitcoin client.

The technical discussion began in a GitHub issue when developers questioned whether Bitcoin Core should continue supporting an encrypted routing layer that sees almost no documented real-world traffic. CJDNS is used for alternative network transport layers to guarantee redundancy, preventing any single point of network-level failure or censorship.

However, redundant routes only function if there is an active mesh of peers participating on the underlying network. Automated testing revealed that a CJDNS-only node setup was unable to establish connections with more than three or four distinct peers at any given time.

The low numbers underscore a serious practical reality: an overlay network with fewer than a dozen accessible routing targets fails to provide the operational redundancy required for a resilient production node. Proponents argue that CJDNS's low usage numbers stem from a lack of user awareness and limited integration in popular turn-key node software distributions, rather than a lack of underlying value.

Developers advocating for removal emphasize the ongoing maintenance burden that CJDNS code imposes on the overall Bitcoin Core software repository. Several Core contributors have offered a 'Concept ACK' toward deprecating the protocol, indicating agreement with the high-level goal of a proposal.