Authentication vs Authorization: Understanding the Difference

Published by Omu Inetimi on July 05, 2024
Authentication vs Authorization: Understanding the Difference

Authentication vs Authorization: Understanding the Difference

In recent times, security in modern applications cannot be overemphasized. It is extremely important to ensure our applications have proper security measures to prevent sensitive data from getting into the wrong hands.

In doing so, two particularly relevant concepts come to mind: authentication and authorization. They are both referred to in shorthand as "Auth" and are frequently used hand in hand when building secure applications, and as a result, their meanings can get intertwined. This article will help you understand what authentication and authorization are, and how to differentiate between these two important aspects of application security.

What is Authentication (AuthN)?

Authentication in computing is defined as the process or action of verifying the identity of a user or process. It's how your application verifies who you say you are. Authentication within the application effectively answers the question "Who are you?".

The goal of authentication is mainly to ensure that only those who have permission can access the application. By verifying the identity of every user, it helps to keep sensitive data safe, block unwanted access, and preserve system security. It's an essential part of the application because in doing so it builds trust between the user and the system.

There are quite a few ways the application can do this:

  1. We have the classic case of username and password - where the user provides their username and the password which is the key to the user's account. This of course assumes that whoever has the password must be the owner of the account, which in modern security situations is not considered the best approach due to the risk of password leaks, phishing, and other methods bad actors could use to gain identification information.

  2. Multifactor authentication is another option. To make the system more secure, this technique combines two or more authentication techniques. Usually, it requires utilizing either something you have (like a security token or smartphone), something you know (like a password), or something you are (like a fingerprint or facial recognition). Two-factor authentication (2FA) is the most popular example and it works by sending you a unique code through SMS or an email after you input your username and password. After that, you input this code into the application to have your identification confirmed. That sent code adds an extra layer of security, making it considerably more difficult for unauthorized users to obtain access even if they have access to your device or account. This combination of the account credentials plus an additional factor is what makes it truly "two-factor" authentication.

  3. Biometric authentication is yet another method of authentication that verifies the user using biometric information. This could be done using the user's bodily characteristics, such as fingerprints, facial IDs, retinal scans, etc., to identify them. Since no two people have the same biometric information, there is very little possibility that an attacker will be able to get around these physical restrictions, making it by far one of the most secure means of verification. This would also mean that the application system must support the hardware that collects the biometric information for verification.

These are just a few examples of the various methods used for authentication.

What is Authorization (AuthZ)?

Authorization, on the other hand, is the act of allowing or refusing access to resources within an application. It often takes place following authentication and establishes the resources and permissions that an authenticated user is granted access to. Authorization essentially answers the question, "What are you allowed to do?".

Authorization is essential to make sure users have the right amount of access within the application and it does so by guaranteeing that only those with the required permission have access to specific information. Implementation of authorization contributes to the overall protection of your application from potential security risks.

There are several ways applications can handle authorization, just to name two:

  1. Role-Based Access Control (RBAC): In this case, users are given permissions according to their positions in an organization. Access rights are tied to specific roles so you could imagine a case where an ordinary user position might only have limited access, whereas an admin might have complete access to all resources. Using this method of authorization makes it so that users only have access to the information necessary for their roles while easing management.
  2. Attribute-Based Access Control (ABAC): In this method, access is granted according to policies and attributes. User properties (such as department and job title), resource properties, and environmental properties (like access time) can all be considered attributes. ABAC offers you a flexible way to handle authorization Because the decisions made are based on a combination of policies and attributes hence giving you a higher level of control.

AuthN vs AuthZ: Key Differences and How They Work Together

Verification vs. Permission:

As previously stated, authentication and authorization serve distinct functions inside the security system. Authentication is used to confirm the identity of a user or process. Consider it as a way to verify yourself at the door by showing your ID. Authorization, on the other hand, focuses on ensuring that specific users have specific permissions after they enter. Think of it as the key card that allows you access to specific locations or resources depending on your position.

Sequential Process:

Authentication always comes before authorization. You could think of it as a 2-step process with authentication always coming first. The system always has to verify who enters it before it can determine what these verified users are permitted to do once they're in.

Integrated Security Approach:

They work together quite well despite their differences. You can think of them as two sides of the same coin: authentication ensures that only valid users can access the program, whereas authorization ensures that those users can only access the resources they are authorized to. It's a team effort from both ends that ensures the security of the entire application is not compromised.

Real-World Scenario

Let's take Twitter for example. Before you log into your Twitter account, you have to provide your username and password. That is authentication; you're proving to Twitter you own that account and Twitter makes sure that only you can access it. After logging in, you can send a tweet, change your profile, view, like, and comment on other users' tweets. However, you cannot change or delete other people's accounts or tweets. You have the authority to manage your own content and engage with others, but you cannot control other people's accounts or carry out administrative tasks assigned to Twitter employees. That's authorization in action.

Why Choosing the Right Authorization Solution Matters

Scalability and Flexibility:

When it comes to authorization, having a scalable and flexible solution is very important. You want your authorization system to be able to scale as your application grows to accommodate the incoming traffic. A scalable authorization solution can handle an increasing number of users and permissions without compromising performance. Flexibility is equally important because it allows you to easily adjust permissions and roles as your application's requirements change. Both ensure that your system remains efficient no matter how much it grows.

Security Best Practices:

Having an effective authorization system is a significant part of maintaining the security of your application. A good authorization setup prevents unauthorized access to sensitive data. By ensuring that only users with the correct permissions can access certain resources, you significantly reduce the risk of security breaches. This not only protects your application but also builds trust with your users.

Outsourcing Complexity:

Development teams often have a natural tendency to implement their own in-house authorization solutions, assuming it's an "easy to solve" problem. However, these homegrown solutions typically require significant maintenance and scaling efforts as the application grows in both user base and complexity. Authorization-as-a-Service solutions address this challenge by shifting the responsibility away from the development team to a finished product that already provides the necessary flexibility and scalability. This approach allows teams to focus on core application features while benefiting from a robust, professionally maintained authorization system.

Cerbos Advantages

Cerbos stands out as a powerful authorization solution with several unique features. Firstly, it offers fine-grained control over permissions, allowing you to create detailed access policies. This means you can create permissions to match the exact needs of your application and users. Cerbos also supports both role-based and attribute-based access control, giving you the flexibility to choose the best approach for your situation. Additionally, it integrates seamlessly with existing systems and scales effortlessly as your application grows. Cerbos provides an open-source version that developers can integrate into their systems for free. You can find the open-source version on the Cerbos GitHub repository here.


We've covered a lot of ground in this article, diving deep into the world of authentication and authorization. By now, you should have a solid understanding of how these two concepts differ and why they're both crucial in keeping your application secure.

To recap, authentication is all about verifying who you are. On the other hand, authorization is about what you're allowed to do once you're inside.

So, if you're looking to take your application's security to the next level, I highly recommend checking out Cerbos. They've got a ton of resources and even a demo that you can explore. Trust me, your application (and your users) will thank you for it.

Book a free Policy Workshop to discuss your requirements and get your first policy written by the Cerbos team