xdsa library

Composite ML-DSA cryptography wrappers and parametrization.

https://datatracker.ietf.org/doc/html/draft-ietf-lamps-pq-composite-sigs

A key signs a message with ML-DSA-65 and Ed25519 at once, and a signature verifies only if both halves do. Keys and signatures round-trip through fixed-size byte arrays. Keys also support DER and PEM serialization.

import 'dart:convert';

import 'package:darkbio_crypto/xdsa.dart' as xdsa;

void example() {
  final secret = xdsa.SecretKey.generate();
  final public = secret.publicKey();

  final signature = secret.sign(utf8.encode('hello'));
  public.verify(utf8.encode('hello'), signature);

  // A key restored from PEM is the same key
  final restored = xdsa.PublicKey.fromPem(public.toPem());
  assert(restored.fingerprint() == public.fingerprint());
}

Classes

Fingerprint

A 256-bit unique identifier for an xDSA key.

PublicKey

An ML-DSA-65 public key paired with an Ed25519 public key for verifying quantum resistant digital signatures.

SecretKey

An ML-DSA-65 private key paired with an Ed25519 private key for creating and verifying quantum resistant digital signatures.

Signature

An ML-DSA-65 signature (3309 bytes) paired with an Ed25519 signature (64 bytes), 3373 bytes in total.