gistfile1.dart

  EncryptedPrivateKey encrypt(Uint8List privKey, KeyParameter aesKey) {
    if(privKey == null || aesKey == null) throw new ArgumentError();
    Uint8List iv = new Uint8List(BLOCK_LENGTH);
    // TODO fill iv with random bytes from securerandom
    ParametersWithIV keyWithIv = new ParametersWithIV(aesKey, iv);
    PaddedBlockCipher cipher = new PaddedBlockCipherImpl(new PKCS7Padding(), new CBCBlockCipher(new AESFastEngine()));
    cipher.init(true, keyWithIv);
    Uint8List encryptedKey = cipher.process(privKey);
    return new EncryptedPrivateKey(encryptedKey, iv);
  }
  
  Uint8List decrypt(EncryptedPrivateKey encryptedPrivKey, KeyParameter aesKey) {
    if(encryptedPrivKey == null || aesKey == null) throw new ArgumentError();
    ParametersWithIV keyWithIv = new ParametersWithIV(aesKey, encryptedPrivKey.iv);
    PaddedBlockCipher cipher = new PaddedBlockCipherImpl(new PKCS7Padding(), new CBCBlockCipher(new AESFastEngine()));
    cipher.init(false, keyWithIv);
    return cipher.process(encryptedPrivKey.encryptedKey);
  }