@Override
  public CryptoService<SecretKeySpec> getCryptoService() {
    return new GCMCryptoService(cryptoServiceConfig);
  }
Instantiates {@link GCMCryptoServiceFactory}
@param verifiableProperties {@link VerifiableProperties} to load configs from
@param registry {@link MetricRegistry} to use
ambry-router/src/main/java/com/github/ambry/router/GCMCryptoServiceFactory.java