Magic Links and One-Time Passwords - A Guide to Passwordless Authentication

If you're a developer, it's your responsibility to keep up with the ever-evolving landscape of internet security. Today, we're going to delve into an exciting facet of modern cybersecurity: one-time passwords and magic links. One-time passwords are a method of passwordless authentication that has been gaining popularity. They allow users to access websites without typing a password or using an app by clicking on a link or copying a code sent over a secure channel.

What Are Magic Links?#

In simplest terms, a magic link is a URL with an embedded one-time password. Clicking on the link authenticates the user, allowing them to access a particular service or application. One-Time Passwords are similar in function to TOTP (Time-based One-Time Password) MFA (Multi-Factor Authentication), but one-time passwords can be used as a primary method of authentication, whereas TOTP can only be used as a secondary method for MFA.

Magic links are a straightforward alternative to usernames and passwords. Instead of asking users to create and remember credentials, we send a one-time-use link or code to their registered email account or phone number. The link/code is unique, so it cannot be used by anyone else. It is also impossible for the user to lose because we can recover it from our servers at any time.

You can provide magic links through many messaging platforms, but email is a very popular delivery option. The concept was first introduced around 2010, and then picked up by major players such as Facebook and Microsoft. This approach has become popular because it's easy for users and administrators alike.

How Does One-Time Password Authentication Work?#

The process starts when a user inputs their email address, phone number, or username into a login form. The backend API service generates a unique token. The service then either attaches it to a URL (creating a "magic link") or provides the token directly. This link or code is then sent to the user. The user clicks the magic link or enters the code into the login form to access the service.

What Are The Benefits Of Using Magic Links#

How Do One-Time Passwords Impact User Experience (UX)?#

It's no secret that users often struggle with password management. The average user is registered on dozens of online platforms, each requiring a unique password. Remembering these is often challenging, leading to frequent password resets, which further degrade user experience. Magic links simplify this process, requiring only access to an email account.

Are One-Time Passwords Secure?#

Despite being the standard for years, passwords are a known security weak point. Users often reuse passwords across platforms or opt for easy-to-remember (and easy-to-guess) options. By using magic links, we eliminate the risk of password reuse or theft. In addition, the temporary nature of one-time passwords also acts as a security advantage, as each code expires after use or after a set period, whichever happens first. This prevents attackers from using them for malicious purposes.

How Hard Is It To Implement One-Time Passwords?#

Implementing a secure password-based system can be a challenge. It involves creating secure password storage, implementing encryption, managing password resets, etc. In comparison, one-time password systems can be simpler to implement and maintain. They don't require any changes to existing infrastructure, which makes them a good choice for small and medium businesses. In addition, they can be implemented with fewer resources than other security solutions such as software-based two-factor authentication (2FA) systems or hardware tokens.

Considerations And Risks Of One-Time Passwords#

While one-time passwords provide an attractive alternative to traditional passwords and forgot password links, it's crucial to consider potential drawbacks.

Are One-Time Passwords Reliant On Email Accounts or Phone Numbers?#

One-Time passwords often rely on the security of the user's email account or phone number. If one of those communication channels is compromised, all services using one-time passwords are potentially at risk. It's thus crucial to encourage users to protect their email accounts with strong security measures, like two-factor authentication.

Closing Thoughts#

One-Time Passwords provide an alternative to traditional password-based authentication, offering improved user experience and security. As developers, it's our role to adapt to these changing paradigms to offer the best possible security solutions to our users. As we move towards a passwordless future, one-time passwords are certainly worth considering.