libomemo-c

Implementation of the ratcheting forward secrecy protocol

This is a fork of libsignal-protocol-c, an implementation of Signal's ratcheting forward secrecy protocol that works in synchronous and asynchronous messaging. The fork adds support for OMEMO as defined in XEP-0384 versions 0.3.0 and later. * OMEMO version 0.3.0 uses the original libsignal-protocol-c implementation with its protocol versions 2 and 3. * OMEMO version 0.4.0+ is implemented using a new protocol version 4 internally. In comparison with protocol version 3, it changes: * HKDF info strings * Protocol buffer encoding * Signature scheme (uses XEd25519 instead of custom "Curve25519 signatures") * Specification-compliant double ratchet * Support for Ed25519 public keys * Various serializations * Removes unused functionality