Access tokens and JSON Web Tokens (JWTs) are two popular approaches for implementing authentication and authorization. Both have their advantages and disadvantages - so making the right choice requires understanding the trade-offs. In this blog, we will explore the trade-offs between using access tokens and using JWTs for authentication and authorization.
Access tokens are strings that are issued by an authentication server when a user logs in to an application. The access token contains information about the user and their permissions. The client application then sends the access token with each subsequent request to the server to verify that the user has the required permissions to access the requested resource.
Access tokens are easy to implement and require minimal setup. They are simple strings that can be stored in cookies or local storage. This makes it easy for developers to add authentication to their applications without having to spend too much time on implementation.
Since access tokens are issued by and checked against an authentication server, they can be revoked at any time. This means that if a user's access needs to be revoked or changed, it can be done quickly and easily. This is particularly useful in large applications with many users.
Access tokens are generally smaller than JWTs, which means they take up less space in requests and responses. This can result in faster network performance, particularly for mobile applications or applications with slow network connections.
Access tokens are vulnerable to attack if they are intercepted by malicious actors. If an attacker gains access to a user's access token, they can use it to impersonate the user and gain access to sensitive data. Access tokens must be encrypted and protected against interception and tampering.
Access tokens are random strings, and so contain no intrinsic information about the user. They require resolution on the server to load user data, such as their ID, preferences and permissions. This can limit the functionality of applications that rely solely on access tokens for authentication.
JSON Web Tokens (JWTs) are a form of access token that contain additional information about the user in the form of JSON objects. They are used to authenticate and authorize users in web applications by passing claims between parties in the form of a digitally signed token.
While access tokens don’t typically expire, JWTs always contain an expiration time claim, ‘exp’. After the expiration time, the server will reject the JWT as expired. This provides an additional layer of security to the authentication process by limiting the window of opportunity for attackers to use stolen or intercepted tokens.
JWTs can contain additional information beyond basic user information, such as user preferences or settings. This makes them more flexible than traditional access tokens and allows them to be used for additional purposes beyond authentication.
JWTs are signed using a secret key known only to the server. When a client presents a signed JWT to the server, the server can verify the authenticity of the token using the signature. This process does not require additional database queries or lookups, so JWTs can be validated quickly and efficiently. This makes them especially useful for web and mobile applications that require fast authentication.
JWTs are more challenging to revoke than traditional access tokens since they are signed. To revoke a user’s access, the server must maintain a Certificate Revocation List of revoked tokens (which can be challenging to manage in distributed systems) or rotate the signing key for all issued tokens (invalidating all users’ login sessions). This can create security risks if a JWT falls into the wrong hands, as it may not be immediately possible to revoke it.
JWTs are more complex to implement than traditional access tokens, requiring additional libraries or frameworks. This can make them more challenging for developers to implement, particularly those who are new to authentication and authorization.
JWTs are larger than traditional access tokens since they contain additional information and claims about the user. This can result in slower network performance, particularly for mobile applications or applications with slow network connections.
Access tokens and JWTs are both useful approaches to authentication and authorization, but they have their trade-offs. Access tokens are simple to implement, scalable, and offer good performance, but they are vulnerable to interception and impersonation attacks. JWTs generally, are more flexible, and lighter weight, but they are more complex to implement, larger in size, and may have limited revocation capabilities.
Ultimately, the choice between access tokens and JWTs depends on the specific needs of your application. If your application requires a simple and lightweight authentication solution, access tokens may be the best choice. If your application requires additional functionality and flexibility, JWTs may be a better fit. Whatever approach you choose, it's essential to prioritize security and ensure that your authentication solution is well-architected and thoroughly tested.