code: public static void decryptFile(File encryptedFile, File result, String password) throws IOException {
          byte[] b = readBytes(encryptedFile);
          String decryptedImageString = new RNCryptorNative().decrypt(new String(b), password);
          byte[] decodedBytes = Base64.decode(decryptedImageString, 0);
          writeBytes(result, decodedBytes);
      }
docs: Decrypts file using password
  @param encryptedFile file which needs to be decrypted
  @param result destination file for decrypted file
  @param password strong generated password
  @throws IOException