A post-quantum mix network providing strong metadata privacy against global passive adversaries.

📄 Paper · 🌐 Website · 📚 Docs · 💬 Community

• katzenpost — monorepo:
  • Mix network: mix server, directory authority
  • Pigeonhole protocol: courier, replica. Uses the mixnet as transport for clients to talk to couriers.
  • Client daemon (kpclientd): mixnet client used by applications, including to reach Pigeonhole couriers.
• hpqc — hybrid post-quantum cryptography library. Provides KEM, NIKE, and signature schemes behind clean interfaces, plus the pieces that make them composable:
  • a KEM combiner that is provably IND-CCA2 in the QROM, based on the KEM Combiners paper
  • a NIKE-to-KEM adapter (an ad-hoc ElGamal construction) so any NIKE can be used as a KEM, and combined with other KEMs via the combiner
  • a signature scheme combiner
  • BACAP, a blinding-and-capability scheme used by Pigeonhole

• kpclientd — the Katzenpost client daemon. Lives in the monorepo at cmd/kpclientd; build with make kpclientd from the repo root. Required by katzenqt.
• katzenqt — Qt group chat client. Talks to kpclientd.

Language bindings for building applications that talk to kpclientd:

• Go — in the monorepo at client2/thin
• Rust and Python — thin_client

• website — source for katzenpost.network

• Use it: build katzenqt and kpclientd (see Clients above) — pre-built packages coming
• Run a node: Admin Guide
• Build on it: Thin Client API
• Contribute: katzenpost/katzenpost — issues and PRs
• Research: Echomix paper and Threat Model

GNU AGPL-3.0 across the org. A small number of submodules use different licenses; see the LICENSE file inside each repository.