DTLS-SRTP

Hybrid Post-Quantum Message Sealing: X25519 + ML-KEM-1024 in Umbera Messenger with Public Rust Tests

Umbera messenger has open-sourced its cryptographic core and published seven Rust tests that anyone can run to verify its hybrid post-quantum message sealing scheme. The design combines X25519 with ML-KEM-1024 so that an attacker must break both algorithms to decrypt a message. Messages are protected by Double Ratchet for forward secrecy, sealed sender packaging, and per-message ephemeral keys derived via HKDF-SHA256 into AES-256-GCM. The relay server stores only an opaque box identifier and encrypted blob with no sender or recipient fields visible. Media calls use DTLS-SRTP end-to-end while TURN servers see only encrypted datagrams. Addresses for message boxes rotate weekly and are derived solely from the shared secret between the two parties.