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Encryption

Both L2PSMessagingPeer and the legacy MessagingPeer use the same end-to-end encryption layer. Only the persistence and transport layer differs between the two — the cryptography is identical. The protocol uses ml-kem-aes for secure communication:
  1. Key generation. Each peer generates a public/private key pair (post-quantum ML-KEM, ML-KEM-768 in the Demos default).
  2. Public key exchange. Peers exchange public keys through their respective server (the L2PS messaging server for L2PSMessagingPeer, the legacy signaling server for MessagingPeer).
  3. Signatures. Peers sign their ML-KEM public key with an ML-DSA signing key from the same unifiedCrypto instance to bind the encryption key to the signing identity.
  4. Message encryption. Messages are encrypted using the recipient’s public key by encapsulating a fresh shared secret per message (this is what gives the protocol its forward-secrecy property).
  5. Message decryption. Recipients use their private key to decapsulate the shared secret and AES-decrypt the payload.
For L2PSMessagingPeer, the encrypted payload is serialized to the wire as SerializedEncryptedMessage: 
interface SerializedEncryptedMessage {
    ciphertext: string       // base64
    nonce: string            // base64 (AES-GCM nonce/IV)
    ephemeralKey?: string    // hex (only when using X25519 ephemeral DH)
}
For MessagingPeer, the same plaintext is serialized using SerializedEncryptedObject from the SDK’s unifiedCrypto (algorithm, serializedCipherText, serializedEncryptedData).