That's what all the systems with "login with Facebook, Google, Twitter, GitHub" use underneath.

### OAuth 1

There was an OAuth 1, which is very different from OAuth2, and more complex, as it included direct specifications on how to encrypt the communication.

It is not very popular or used nowadays.

OAuth2 doesn't specify how to encrypt the communication, it expects you to have your application served with HTTPS.

/// tip

	"$content-type":            true,
	"$content-disposition":     true,
	"$content-encoding":        true,
	"$expires":                 true,
	"$key":                     true,
	"$success_action_redirect": true,
	"$redirect":                true,
	"$success_action_status":   true,
	"$x-amz-algorithm":         false,
	"$x-amz-credential":        false,
	"$x-amz-date":              false,
}

var postPolicyIgnoreKeys = map[string]bool{

                                        Valid Options: ANY, ROUTE, REDIRECT, DIRECT_RESPONSE
                                      enum:
                                      - ANY
                                      - ROUTE
                                      - REDIRECT
                                      - DIRECT_RESPONSE
                                      type: string

    /** The path of the HTML: /error/notFound.jsp */
    HtmlNext path_Error_NotFoundJsp = new HtmlNext("/error/notFound.jsp");

    /** The path of the HTML: /error/redirect.jsp */
    HtmlNext path_Error_RedirectJsp = new HtmlNext("/error/redirect.jsp");

    /** The path of the HTML: /error/system.jsp */
    HtmlNext path_Error_SystemJsp = new HtmlNext("/error/system.jsp");

    /** The path of the HTML: /footer.jsp */

        verifyToken(() -> asHtml(path_AdminGeneral_AdminGeneralJsp));

        updateConfig(fessConfig, form);
        saveInfo(messages -> messages.addSuccessUpdateCrawlerParams(GLOBAL));
        return redirect(getClass());
    }

    public static void updateConfig(final FessConfig fessConfig, final EditForm form) {
        fessConfig.setLoginRequired(isCheckboxEnabled(form.loginRequired));

            saveInfo(messages -> messages.addSuccessStartCrawlProcess(GLOBAL));
        } else {
            saveError(messages -> messages.addErrorsFailedToStartCrawlProcess(GLOBAL));
        }
        return redirect(AdminWizardAction.class);
    }

## Caveat

   * syntax</a>.
   *
   * @return a new, empty {@code HashMap}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
  public static <K extends @Nullable Object, V extends @Nullable Object>
      HashMap<K, V> newHashMap() {
    return new HashMap<>();
  }

  /**

   * syntax</a>.
   *
   * @return a new, empty {@code HashMap}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
  public static <K extends @Nullable Object, V extends @Nullable Object>
      HashMap<K, V> newHashMap() {
    return new HashMap<>();
  }

  /**

                }
            }
            throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url + " (Redirect Loop)");
        });
    }

    public void setGeneratorList(final List<String> generatorList) {
        this.generatorList = generatorList;
    }

    @Override
    public String getName() {