public String generateRandomSecretKey() {
    return aesGCMCipher.generateRandomSecretKey();
  }
@Test
  public void generate_secret_key() {
    Encryption encryption = new Encryption(null);
    String key1 = encryption.generateRandomSecretKey();
    String key2 = encryption.generateRandomSecretKey();
    assertThat(key1).isNotEqualTo(key2);
  }