Crate metamorphic_crypto 

metamorphic-crypto

Zero-knowledge end-to-end encryption core for the Metamorphic platform.

This library implements the cryptographic operations required by all Metamorphic clients (web/WASM, iOS/UniFFI, Android/UniFFI). It produces byte-compatible ciphertext with the existing JavaScript implementation so that data encrypted by one client can be decrypted by any other.

Security guarantees

• All secret key material is [Zeroize]-on-drop
• No unsafe code
• Constant-time comparisons via the underlying RustCrypto crates
• Randomness sourced directly from the OS CSPRNG (getrandom)

Ciphertext formats

Format	Layout
Secretbox	nonce (24B) || ciphertext (len + 16B MAC)
box_seal	ephemeral_pk (32B) || box ciphertext
Hybrid v1 (Cat-1)	0x01 || ML-KEM-512 ct (768B) || X25519 eph pk (32B) || nonce (24B) || secretbox ct
Hybrid v2 (Cat-3)	0x02 || ML-KEM-768 ct (1088B) || X25519 eph pk (32B) || nonce (24B) || secretbox ct
Hybrid v3 (Cat-5)	0x03 || ML-KEM-1024 ct (1568B) || X25519 eph pk (32B) || nonce (24B) || secretbox ct

Signature format

Composite ML-DSA + Ed25519 signatures (see [sign]); strict-AND verification.

Component	Layout
signature	tag || ed25519_sig (64B) || ml_dsa_sig
public_key	tag || ed25519_pk (32B) || ml_dsa_pk
secret_key	tag || ed25519_seed (32B) || ml_dsa_seed (32B)

Re-exports

pub use error::CryptoError;

pub use b64::parse_salt_from_key_hash;

pub use box_seal::box_seal;

pub use box_seal::box_seal_open;

pub use hash::sha3_256;

pub use hash::sha3_512;

pub use hash::sha3_512_with_context;

pub use hash::sha256;

pub use hash::sha512;

pub use hybrid::HybridKeyPair;

pub use hybrid::SecurityLevel;

pub use hybrid::generate_hybrid_keypair;

pub use hybrid::generate_hybrid_keypair_512;

pub use hybrid::generate_hybrid_keypair_1024;

pub use hybrid::generate_hybrid_keypair_with_level;

pub use hybrid::hybrid_open;

pub use hybrid::hybrid_seal;

pub use hybrid::hybrid_seal_512;

pub use hybrid::hybrid_seal_1024;

pub use hybrid::hybrid_seal_with_level;

pub use hybrid::is_hybrid_ciphertext;

pub use kdf::derive_session_key;

pub use keys::KeyPair;

pub use keys::decrypt_private_key;

pub use keys::encrypt_private_key;

pub use keys::generate_key;

pub use keys::generate_keypair;

pub use keys::generate_salt;

pub use recovery::RecoveryKey;

pub use recovery::decrypt_private_key_with_recovery;

pub use recovery::encrypt_private_key_for_recovery;

pub use recovery::generate_recovery_key;

pub use recovery::recovery_key_to_secret;

pub use seal::seal_for_user;

pub use seal::seal_for_user_with_level;

pub use seal::unseal_from_user;

pub use secretbox::decrypt_secretbox;

pub use secretbox::decrypt_secretbox_to_string;

pub use secretbox::encrypt_secretbox;

pub use secretbox::encrypt_secretbox_string;

pub use sign::HybridSignatureKeyPair;

pub use sign::SIGN_CONTEXT_V1;

pub use sign::SignatureLevel;

pub use sign::derive_public_key;

pub use sign::generate_signing_keypair;

pub use sign::generate_signing_keypair_44;

pub use sign::generate_signing_keypair_87;

pub use sign::generate_signing_keypair_with_level;

pub use sign::sign;

pub use sign::verify;

Modules

b64

Base64 utilities (standard alphabet, with padding).

box_seal

X25519 sealed box (anonymous public-key encryption).

error

Error types for the crypto library.

hash

Cryptographic hash functions (SHA-3 and SHA-2 families).

hybrid

Hybrid post-quantum KEM: ML-KEM-512 + X25519 (Cat-1), ML-KEM-768 + X25519 (Cat-3, default), and ML-KEM-1024 + X25519 (Cat-5).

kdf

Argon2id key derivation.

keys

Key generation and private-key encrypt/decrypt helpers.

recovery

Recovery key generation and encoding.

seal

Unified seal/unseal that auto-detects hybrid (v2/v3) vs legacy (v1) format.

secretbox

XSalsa20-Poly1305 authenticated encryption (NaCl secretbox).

sign

Hybrid post-quantum signatures: ML-DSA (FIPS 204) + Ed25519 composite.