Putting Verification Links in Place for Email Password Resets in Azure B2C

Lina Fontaine
Saturday, March 16, 2024 at 8:25:45 PM
Azure

Enhancing User Authentication with Azure B2C: From Code to Link

It is a special difficulty to change the user authentication landscape in password reset flows, especially for apps that use Azure B2C. Email-based verification codes have historically been used as a simple, albeit laborious, way to confirm user identification. This procedure frequently requires the user to transfer between the application that requests authentication and their email program, which could cause friction and lead to user attrition. A more simplified method has been made possible by the introduction of delivering bespoke email templates using SendGrid and similar services, although switching from a straightforward verification code to a more user-friendly verification link is not always easy.

The idea for switching to a verification link—which is similar to procedures observed in signup invitation flows—came from the goal of improving user experience through the expediting of the password reset procedure. In addition to attempting to minimize the number of steps needed for a user to authenticate, this action also greatly reduces the possibility of mistakes occurring during the verification process. The lack of explicit, direct examples or documentation specific to applying this modification in the context of Azure B2C password resets presents a problem, though. This has prompted questions in the development community from those who have already started this path, asking for their experiences and ideas.

Command Description
using Microsoft.AspNetCore.Mvc; Contains the namespaces required by the MVC framework for controller functionality in.NET Core applications.
using System; Consists of the System namespace, which offers base classes and basic classes that provide frequently used data types, events, and event handlers, as well as interfaces, attributes, and processing exception support.
using System.Security.Cryptography; Offers a variety of cryptographic services, such as safe data encoding and decoding, random number generation, and many more.
Convert.ToBase64String() Converts an array of unsigned 8-bit integers to the base-64-encoded string representation of that array.
RandomNumberGenerator.GetBytes(64) Uses the cryptographic service provider to generate a series of secure random bytes (CSP). It creates 64 bytes in this case to be used as a token.
<!DOCTYPE html> Specifies the HTML version and document type.
>Head>, >title>, >body>, >script>, and >html> JavaScript code can be embedded into HTML documents using basic HTML tags.
window.onload An event in JavaScript that is carried out once the page has loaded completely, with all frames, objects, and pictures included.
new URLSearchParams(window.location.search) Creates an instance of the URLSearchParams object to facilitate working with a URL's query string and extracting the token parameter.

Overview of Implementation: Email Verification Link

The backend script and the frontend page are the two primary parts of the Azure B2C SendGrid procedure that exchanges a verification code for a verification link. The backend script, written in.NET Core, is in charge of creating a distinct, secure token in response to a password reset request. To further security, this token is then kept in a database together with the user's email address and a timestamp to make sure it expires after a predetermined amount of time. In order to do this, the script generates a byte array using the 'RandomNumberGenerator' class and uses 'Convert.ToBase64String' to convert it to a string representation. The token in this case is this string. The script then sends the user an email by utilizing SendGrid's capabilities. The link in this email takes the user to a frontend page where they may finish the password reset procedure by embedding the produced token as a parameter.

JavaScript is used to enhance a basic HTML page to create the frontend component. As soon as the user accesses this website through the verification link, the token will be taken from the URL. While 'new URLSearchParams(window.location.search)' retrieves the token from the URL, 'window.onload' guarantees that the script executes as soon as the page loads. After then, the token can be returned to the server to be validated, confirming both its legitimacy and the user's consent to change their password. The smooth transition from frontend token validation to backend token creation creates a safe and convenient password reset procedure that removes the need for manual code entry and improves user experience overall.

Using Verification Links in the Azure B2C Password Reset Flow Modification

.NET Core Backend Implementation

using Microsoft.AspNetCore.Mvc;
using System;
using System.Security.Cryptography;
public class ResetPasswordController : Controller
{
    [HttpPost]
    public IActionResult GenerateLink([FromBody]string email)
    {
        var token = Convert.ToBase64String(RandomNumberGenerator.GetBytes(64));
        // Store the token with the user's email and expiration in your database
        // Send the email with SendGrid, including the token in a verification link
        return Ok(new { Message = "Verification link sent." });
    }
}

Handling Verification Link Redirection

JavaScript and HTML for Client-Side

<!DOCTYPE html>
<html>
<head>
    <title>Password Reset Verification</title>
</head>
<body>
    <script>
        window.onload = function() {
            // Extract token from URL
            var token = new URLSearchParams(window.location.search).get('token');
            // Call your API to verify the token and allow the user to reset their password
        };
    </script>
</body>
</html>

Using Verification Links to Improve User Authentication in Azure B2C

In the Azure B2C password reset cycle, switching from a typical verification code to a verification link offers a more secure and efficient user experience. By offering a straightforward, one-time link for password resets, this method reduces the possibility of interception or illegal use while also streamlining the process for users and improving security. The underlying technology entails generating a special, secure token linked to the user's request to reset their password. This token is subsequently included in an email link that is provided to the user. This technique makes use of cloud services like as SendGrid and Azure B2C, which are scalable and dependable, to guarantee a reliable and effective reset procedure.

The creation of a secure token, keeping this token with an expiration date, and making sure the user receives the email with the link securely are all necessary steps in the implementation of this system. Before permitting the user to reset their password, the system must validate the token once the user clicks the link to make sure it is still valid and hasn't expired. This process adds an extra degree of protection by guaranteeing that only the email recipient can access the reset link, which enhances user experience by making password resets easier.

Frequently Asked Questions about Implementing Verification Links

  1. What security benefits does the verification link offer?
  2. By guaranteeing that the password reset procedure is only started over a secure, one-time link that is difficult to intercept or replicate, the verification link increases security.
  3. Does the link for verification expire?
  4. To improve security and make sure the link is utilized right away, it is possible to configure the verification link to expire after a specified amount of time.
  5. Can I alter the email template that was received along with the verification link?
  6. Yes, you can customize email templates with services like SendGrid to make sure the email with the verification link fits your branding and user communication guidelines.
  7. What occurs if the user does not get the link for verification?
  8. It is imperative to offer users the choice to either resend the verification link or call support in order to facilitate the password reset procedure.
  9. Is it possible to integrate this verification link process with the current authentication systems?
  10. It is possible to combine the verification link procedure with the majority of the current authentication systems, albeit achieving a smooth integration may need some customisation.

The addition of a verification link to password reset email templates, rather than the customary code, is a major improvement in terms of security and user experience for Azure B2C applications. This approach minimizes the possibility of codes being intercepted or misused, which adds an additional degree of protection while also streamlining the process for users and making it less error-prone and more intuitive. Developers may make sure that these emails are delivered safely and in accordance with the most recent best practices in digital communication by integrating services such as SendGrid. Additionally, this strategy creates opportunities for extra improvements, such customized URLs for a more branded user experience and thorough link engagement data. Verification links can ultimately greatly decrease the difficulty of the password reset procedure, promoting improved security habits among users and building confidence in the platform's dedication to protecting user data.