Module crypto 

Message-level cryptography for the Zoe protocol

This module provides cryptographic primitives for message encryption, key derivation, and mnemonic-based key management used in the Zoe messaging protocol.

Key Features

• ChaCha20-Poly1305 encryption for message content
• BIP39 mnemonic phrase support for key derivation
• Ed25519 and ML-DSA key generation from mnemonics
• Self-encryption and ephemeral ECDH patterns
• Argon2 key derivation with configurable parameters

Structs

Argon2Params

ChaCha20Poly1305Content

Minimal encrypted content for wire protocol messages Optimized for space - no key_id since it’s determined by channel context

Ed25519SelfEncryptedContent

Ed25519-derived ChaCha20-Poly1305 encrypted content Simple self-encryption using only the sender’s ed25519 keypair derived from mnemonic Only the sender can decrypt this content (encrypt-to-self pattern) Public key is available from message sender field - no need to duplicate

EncryptionKey

ChaCha20-Poly1305 encryption key

EphemeralEcdhContent

Ephemeral ECDH ChaCha20-Poly1305 encrypted content Simple public key encryption using ephemeral X25519 keys Anyone can encrypt for the recipient using only their public key

KeyDerivationInfo

Information about how a key was derived

MlDsaSelfEncryptedContent

ML-DSA-derived ChaCha20-Poly1305 encrypted content Simple self-encryption using only the sender’s ML-DSA keypair derived from mnemonic Only the sender can decrypt this content (encrypt-to-self pattern) Public key is available from message sender field - no need to duplicate

MnemonicPhrase

Mnemonic phrase for key derivation

Enums

CryptoError

KeyDerivationMethod

Key derivation methods supported by the system

PqxdhEncryptedContent

PQXDH encrypted content for asynchronous secure communication

Functions

ed25519_to_x25519_private

Convert Ed25519 private key to X25519 private key Both curves use the same underlying Curve25519

ed25519_to_x25519_public

Convert Ed25519 public key to X25519 public key Derives X25519 public key from the corresponding Ed25519 private key Note: This is a simplified approach that requires the private key

ed25519_to_x25519_public_from_verifying_key

Convert Ed25519 public key (VerifyingKey) to X25519 public key Uses curve25519-dalek’s Edwards to Montgomery conversion to match the same conversion that happens in the private key derivation path

generate_ed25519_from_mnemonic

Generate an ed25519 signing key from a mnemonic phrase

generate_ml_dsa_from_mnemonic

Generate an ML-DSA signing key from a mnemonic phrase

recover_ed25519_from_mnemonic

Recover an ed25519 signing key from a mnemonic phrase (deterministic)

recover_ml_dsa_from_mnemonic

Recover an ML-DSA signing key from a mnemonic phrase (deterministic)