docs: protected void initPasswordDigest() {
      if(saltGenerator == null) {
        saltGenerator = new Default16ByteSaltGenerator();
      }
      if (passwordEncryptor == null) {
        passwordEncryptor = new Sha512HashDigest();
      }
      if(customPasswordChecker == null) {
        customPasswordChecker = Collections.emptyList();
      }
      if(passwordManager == null) {
        passwordManager = new PasswordManager(passwordEncryptor, customPasswordChecker);
      }
    }