code: public static byte[] encryptAsBytes(final String plainText) throws Exception {
          final SecretKey secretKey = KeyManager.getInstance().getSecretKey();
          return encryptAsBytes(secretKey, plainText);
      }
docs: Encrypts the specified plainText using AES-256. This method uses the default secret key.
  @param plainText the text to encrypt
  @return the encrypted bytes
  @throws Exception a number of exceptions may be thrown
  @since 1.3.0