A detailed technical roadmap for adding end-to-end encryption (E2EE) to ActivityPub/Fediverse, outlining three interdependent goals: a Fundamental Goal (encrypted messaging via MLS/RFC 9420), a Security Goal (authenticated KeyPackages via digital signatures), and an Authenticity Goal (decentralized key transparency). The post breaks down the remaining work across MLS library implementations in multiple languages, post-quantum ciphersuite adoption, HTTP Message Signatures with ML-DSA-44, FEP-521a multi-key support, and a Fediverse Auxiliary Service Provider for key transparency. It also addresses adoption challenges including third-party security audits, funding needs, and the importance of non-cryptographer contributors helping with accessibility, documentation, and UX.
