code: public static String decrypt(String keyBase64, String encrypted) {
          return decrypt(Base64.decodeBase64(keyBase64.getBytes(StandardCharsets.UTF_8)), encrypted);
      }
docs: Decrypt text that was encrypted with the provided encrypt method in this class.
  
  @param keyBase64
  256 bit key base64 encoded
  @param encrypted
  encrypted text
  @return plain text