cryptUnprotectData function

Future<Uint8List?> cryptUnprotectData(Uint8List encryptedData)

Implementation

Future<Uint8List?> cryptUnprotectData(Uint8List encryptedData) async {
  final encryptedBlob = calloc<CRYPT_INTEGER_BLOB>();
  final decryptedBlob = calloc<CRYPT_INTEGER_BLOB>();

  try {
    // Allocate and set the input DATA_BLOB
    encryptedBlob.ref.pbData = calloc<Uint8>(encryptedData.length);
    encryptedBlob.ref.cbData = encryptedData.length;
    encryptedBlob.ref.pbData
        .asTypedList(encryptedData.length)
        .setAll(0, encryptedData);

    // Call CryptUnprotectData
    final result = CryptUnprotectData(
      encryptedBlob,
      nullptr,
      nullptr,
      nullptr,
      nullptr,
      0,
      decryptedBlob,
    );

    if (result == 0) {
      // Decryption failed
      final error = GetLastError();
      print('CryptUnprotectData failed with error: $error');
      return null;
    } else {
      // Decryption succeeded, copy the output data
      final decryptedData =
          decryptedBlob.ref.pbData.asTypedList(decryptedBlob.ref.cbData);
      return Uint8List.fromList(decryptedData);
    }
  } finally {
    // Free allocated memory
    if (encryptedBlob.ref.pbData != nullptr)
      calloc.free(encryptedBlob.ref.pbData);
    if (decryptedBlob.ref.pbData != nullptr)
      LocalFree(decryptedBlob.ref.pbData);
    calloc.free(encryptedBlob);
    calloc.free(decryptedBlob);
  }
}