public Encrypter encryptionKeyDerivedFrom(String secretName){
  checkArgument(!secretName.isEmpty());
  return new Encrypter(secretName);
}

public Encrypter encryptionKeyDerivedFrom ( String secretName ) { checkArgument ( ! secretName . isEmpty ( ) ) ; return new Encrypter ( secretName ) ; }
builds an encrypter using key derived from the provided secret name .
