code: private static void sanityCheckOnCipherBytes(String cipherText,
                                                   byte[] cipherBytes) {
          if (cipherBytes.length % 2 != 0) {
              throw new IllegalStateException("Ciphered text decodes to an odd number of bytes! Text='"
                      + cipherText
                      + "', decodes to "
                      + cipherBytes.length
                      + " bytes.");
          }
      }
docs: If the cipher text decodes to an odd number of bytes, we can't go on!