1. Cryptographic Primitives
- • Key Exchange: Curve25519 (X25519)
- • Symmetric Cipher: AES-256-GCM
- • Key Derivation Function: HKDF-SHA256
- • Signature Verification: Ed25519
- • Real-Time Transport: WebRTC SRTP (DTLS-SRTP)
2. On-Device Local Storage
Local databases on user devices are encrypted via SQLCipher with 256-bit AES keys stored exclusively inside OS Keychains (iOS Keychain / Android Keystore).
3. Session Isolation
Independent ratchet keys are assigned to each conversation session. A compromise of one session key cannot decrypt past or future communication.