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Two-Factor Authentication with Authy, Java and Servlets

As of November 2022, Twilio no longer provides support for Authy SMS/Voice-only customers. Customers who were also using Authy TOTP or Push prior to March 1, 2023 are still supported. The Authy API is now closed to new customers and will be fully deprecated in the future.

For new development, we encourage you to use the Verify v2 API.

Existing customers will not be impacted at this time until Authy API has reached End of Life. For more information about migration, see Migrating from Authy to Verify for SMS.

This Java Servlets sample application demonstrates two-factor authentication (2FA) using Authy. To run this sample app yourself, download the code and follow the instructions on GitHub.

Adding two-factor authentication (2FA) to your web application increases the security of your user's data. Multi-factor authentication determines the identity of a user by validating first by logging into the app, and then through their mobile devices using Authy.

For the second factor, we will validate that the user has their mobile phone by either:

  • Sending them a OneTouch push notification to their mobile Authy app or
  • Sending them a one-time token in a text message sent with Authy via Twilio.
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        Java Application

        See how VMware uses Authy 2FA to secure their enterprise mobility management solution.

        Let's get started!

        Configure Authy

        If you haven't already, now is the time to sign up for Authy. Create your first application, naming it as you wish. After you create your application, your production API key will be visible on your dashboard:

        Authy API Key

        Once we have an Authy API key, we store it on this .env file, which helps us set the environment variables for our app.

        You'll also want to set a callback URL for your application in the OneTouch section of the Authy dashboard. See the project's README for more details.

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              Configure Authy


              Let's take a look at how we register a user with Authy.

              Register a user using Authy

              Register a User with Authy

              When a new user signs up for our website, we call this controller, which handles saving our new user to the database as well as registering the user with Authy.

              All Authy needs to get a user set up for your application is the email, phone number and country code. In order to do two-factor authentication, we need to make sure we ask for these things at the point of sign up.

              Once we register the user with Authy we can get the user's authy_id back. This is very important since it's how we will verify the identity of our User with Authy.

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                    Register a User with Authy


                    Having registered our user with Authy, we then can use Authy's OneTouch feature to log them in.

                    See how to log a user in with Authy

                    Log in with Authy OneTouch

                    When a User attempts to log in to our website, we will ask them for a second form of identification. Let's take a look at OneTouch verification first.

                    OneTouch works as follows:

                    • We check that the user has the Authy app installed.
                    • In case they do, they will receive a push notification on their device.
                    • The user hits Approve in their Authy app.
                    • Authy makes a POST request to our app with an approved status.
                    • We log the user in.
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                          Implement One Touch Approval


                          Now let's look at how to send a OneTouch request.

                          How to send a OneTouch request

                          Send the OneTouch Request

                          When our user logs in, our app decides which two-factor authentication provider will be used. It can be Authy OneTouch or an SMS token.

                          Authy OneTouch will be used when the user has a registered OneTouch device.

                          We use the sendApprovalRequest method to create an approval request. It takes an ApprovalRequestParamater object with at least the following properties configured:

                          • The Authy user ID.
                          • The message that will be displayed in the device.

                          Here is an example about how to build the parameters object.

                          ApprovalRequestParams parameters = new ApprovalRequestParams.Builder(
                            "Request login to Twilio demo app")
                            .addDetail("email", "")
                            .addDetail("name", "Alice")
                            .addHiddenDetail("phoneNumber", "555-5555")
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                                Send the OneTouch Request


                                Once we send the request we need to update our user's AuthyStatus based on the response. But first we have to register a OneTouch callback endpoint.

                                See how to register a callback endpoint

                                Configuring the OneTouch callback

                                In order for our app to know what the user did after we sent the OneTouch request, we need to register a callback endpoint with Authy.

                                Note: In order to verify that the request is coming from Authy, we've written the helper method validate that will halt the request if it appears that it isn't coming from Authy.

                                Here in our callback, we look up the user using the Authy ID sent with the Authy POST request. Ideally at this point we would probably use a websocket to let our client know that we received a response from Authy. However for this version we're going to keep it simple and just update the AuthyStatus on the User. What our client-side code needs to do is to check for user.AuthyStatus == "approved" before logging him/her in.

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                                      Configure OneTouch Callback to validate request


                                      Our application is now capable of using Authy for two-factor authentication. However, we are still missing an important part: the client-side code that will handle it.

                                      How Unsuccessful OneTouch Callbacks are disabled

                                      Disabling Unsuccessful Callbacks

                                      Scenario: The OneTouch callback URL provided by you is no longer active.

                                      Action: We will disable the OneTouch callback after 3 consecutive HTTP error responses. We will also

                                      • Set the OneTouch callback URL to blank.
                                      • Send an email notifying you that the OneTouch callback is disabled with details on how to enable the OneTouch callback.

                                      How to enable OneTouch callback? You need to update the OneTouch callback endpoint, which will allow the OneTouch callback.

                                      Visit the Twilio Console: Console > Authy > Applications > {ApplicationName} > Push Authentication > Webhooks > Endpoint/URL to update the Endpoint/URL with a valid OneTouch callback URL.

                                      Handle authentication in the browser

                                      Handle Two-Factor in the Browser

                                      We've already taken a look at what's happening on the server side, so let's step in front of the cameras and see how our JavaScript is interacting with those server endpoints.

                                      When we expect a OneTouch response, we will begin polling /authy/status until we see Authy status is not empty.

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                                            Poll the server until we see the result of the Authy OneTouch login


                                            Let's take a closer look at how we check the login status on the server.

                                            Check the user's login status

                                            Check Login Status

                                            This is the endpoint that our JavaScript is polling. It is waiting for the user Authy status.

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                                                  Check Login Status


                                                  Finally, we can confirm the login.

                                                  Confirm the login

                                                  Finish the 2FA Step

                                                  If the AuthyStatus is approved, the user will be redirected to the account page, otherwise we'll show the login form with a message that indicates the if the request was denied or unauthorized.

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                                                        Redirect user to the right page based based on authentication status


                                                        That's it! We've just implemented two-factor auth using three different methods and the latest in Authy technology.

                                                        Where to Next?

                                                        Where to Next?

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