init method

@override void init(bool forEncryption, CipherParameters params)

Initializes this for addition of AAD and en/decryption of data.

Implementation

@override
void init(bool forEncryption, CipherParameters params) {
  _forEncryption = forEncryption;
  _initParams = params;
  Uint8List initNonce;
  Uint8List? initAAD;

  if (params is AEADParameters) {
    _macSize = params.macSize ~/ 8;
    _keyParam = params.parameters as KeyParameter;
    initNonce = params.nonce;
    initAAD = params.associatedData;
  } else if (params is ParametersWithIV) {
    _keyParam = params.parameters as KeyParameter;
    initNonce = params.iv;
  } else {
    throw ArgumentError(
        '${params.runtimeType} is not ParametersWithIV or AEADParameters',
        'params');
  }

  _nonceMac = Uint8List(_blockSize);
  _cMac
    ..init(_keyParam)
    ..update(
        Uint8List(_blockSize)..[_blockSize - 1] = _nonceTAG, 0, _blockSize)
    ..update(initNonce, 0, initNonce.length)
    ..doFinal(_nonceMac, 0);

  _aadFinished = false;
  _aadMac = Uint8List(_blockSize);
  _cMac
    ..init(_keyParam)
    ..update(
        Uint8List(_blockSize)..[_blockSize - 1] = _aadTAG, 0, _blockSize);
  if (initAAD != null) processAADBytes(initAAD, 0, initAAD.length);

  _cipherMac = Uint8List(_blockSize);
  _ctr.init(_forEncryption, ParametersWithIV(_keyParam, _nonceMac));

  _bufBlock = Uint8List(_macSize);
  _bufOff = 0;
  _bufFull = false;
}