About the project
umbra is an end-to-end encrypted communication protocol and client designed for journalists, government officials and intelligence professionals operating in high-threat environments. It is serverless — there is no central server — and built on zero-metadata principles: traffic runs over embedded Arti (pure-Rust Tor) v3 onion services, and message contents live in RAM only.
The cryptographic core is complete and continuously tested: a PQXDH handshake combining X25519 with ML-KEM-768 (FIPS 203), the Signal-spec Double Ratchet, ChaCha20-Poly1305 AEAD and ML-DSA-65 signed pre-keys (FIPS 204).
Highlights
- Post-quantum cryptography PQXDH handshake (X25519 + ML-KEM-768), Double Ratchet and ChaCha20-Poly1305 with constant-time verification.
- Embedded Tor transport Pure-Rust Arti with persistent v3 onion identities, vanguards-lite circuit pinning and burst-level cover traffic.
- Hostile-environment hardening Landlock zero-FS sandbox, seccomp-BPF allowlist with a kernel-level network kill-switch, memory locks and zeroize everywhere.
- Verified by construction 122 test cases, proptest, fuzzing, ASan nightly CI and weekly mutation testing on every push.