private static SecretKey generateSymmetricKey() throws Exception {
    KeyGenerator generator = KeyGenerator.getInstance(KEY_ALGORITHM);
    SecureRandom random = new SecureRandom();
    generator.init(KEY_LENGTH_BITS, random);
    logger.debug("Generate Key");
    return generator.generateKey();
    // return new SecretKeySpec(Hex.decodeHex("cb024600dce7148b8ddc5d6c111fbd85".toCharArray()),
    // KEY_ALGORITHM);

  }
  public void generate_new_aes_key() {

    try {
      KeyGenerator localKeyGenerator = KeyGenerator.getInstance("AES");
      localKeyGenerator.init(128, SecureRandom.getInstance("SHA1PRNG"));
      //        aes_key = Base64.encodeBase64String(localKeyGenerator.generateKey().getEncoded());
      aes_key =
          new String(Base64.encode(localKeyGenerator.generateKey().getEncoded(), Base64.DEFAULT));
    } catch (NoSuchAlgorithmException localNoSuchAlgorithmException) {
      System.out.println(localNoSuchAlgorithmException);
    }
    return;
  }