decapsulate method

@override Future<Uint8List> decapsulate(Uint8List secretKey, Uint8List ciphertext)

Recover the shared secret from ciphertext using secretKey.

Implementation

@override
Future<Uint8List> decapsulate(
    Uint8List secretKey, Uint8List ciphertext) async {
  XWingCore.checkDecapsulationInputs(secretKey, ciphertext);
  final ct = XWingCore.splitCiphertext(ciphertext);

  final _Expanded e = await _expand(secretKey);
  try {
    final Uint8List ssM =
        await _mlKem.decapsulate(e.mlKemKeyPair.secretKey, ct.mlKem);
    final Uint8List ssX = await _x25519.dh(e.x25519Secret, ct.x25519);
    return XWingCore.combine(ssM, ssX, ct.x25519, e.x25519Public);
  } finally {
    _mlKem.releaseKeyPair(e.mlKemKeyPair);
  }
}