Source-available post-quantum messenger – crypto core on GitHub

Source-available post-quantum messenger – crypto core on GitHub

PhantomChatCrypto is the cryptographic core of the Phantom Chat messenger (by Veilus Digital), extracted verbatim from the iOS app and made source-available for public review. It implements post-quantum key encapsulation (ML-KEM-768 / FIPS 203), hash functions (SHA3-256/512, SHAKE128/256 / FIPS 202), a hybrid key exchange combining classical X3DH with Kyber (PQXDH), and the Signal Double Ratchet for forward secrecy. All code is written in pure Swift and includes a comprehensive test suite with known-answer tests, correctness checks, and interoperability tests against Apple's CryptoKit (macOS 26+). The authors explicitly state the implementation has not yet undergone a paid third-party audit and invite scrutiny. The repository is provided under a source-available license that permits review and compilation but prohibits reuse in other products.