Authentication vs Authorization: Key Differences You Should Know

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October 2, 2023

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Authentication VS Authorization: what is the difference?

Authentication and Authorization are two important processes for the majority of software we use.
While frequently used together especially in securing web and mobile applications, they are two separate concepts. 
This article will explain the main differences and how these two processes work together. 

What Is Authentication?

Authentication acts as the entry point to an application, determining whether to allow you entry. It comes before authorization and confirms who you are. Each time you log in with your username and password, you're going through authentication.

Many methods exist for authentication beyond just passwords:

  • Authentication apps create one-time passwords.
  • Biometrics, like using your fingerprint to unlock your mobile phone.
  • Passkeys, which use advanced cryptography to replace passwords.
  • Security tokens, like a key-card that provides access.

Sometimes, a system might ask for several proofs of identity before letting you in.
We call this method Multi-Factor Authentication (MFA). MFA boosts security by using a combination of things you know, have, and are.

To learn more about these methods, read our article on why authentication matters.

What is Authorization?

Authorization is the process that determines what you can access and what you can do with your access. 

Access can be given to a person, program or a device. Access can be specific to a resource and also decide what actions you can perform.

Take a workplace example: an employee logs in using a username and password—that's authentication. But what files they can open, which apps they may use, and their level of network access. This is all decided by authorization, based on their role and privileges. 

Similarly, in software or digital services, authorization ensures that users can only reach data or perform allowed actions. This helps maintain security and uphold policy rules.

In practice, authorization employs an access token, like a JavaScript Web Token (JWT). The JWT shares details about the user's privileges. This method is part of how authorization works to control access and manage client privileges.

You might also hear terms like access control or client privileges used to describe what authorization does.

What Are the Differences Between Authentication and Authorization?

Authentication and Authorization are vital yet distinct processes that jointly secure your app. Let's explore their main differences:

Authentication: This process verifies a user, system, or application's identity to confirm they are who they say they are. Key methods include:

  • Using usernames, passwords, biometrics, two-factor, and multi-factor authentication.
  • Employing digital certificates or security tokens.
  • For instance, when you log into your email with a username and password, authentication is at work.
  • If authentication fails, it means the system cannot verify the user’s identity because of incorrect credentials.

Authorization: After authentication, this process determines what the user can access, and what actions they can perform. It Involves:

  • Granting or denying access based on permissions.
  • Systems like access control lists (ACL), role-based access control (RBAC), or attribute-based access control (ABAC) are used to decide what actions users can take.
  • An example is being able to read and delete your emails, but not being able to delete someone else’s.
  • Authorization failure occurs when an authenticated user is denied from performing an action.

In essence, authentication acts as a gatekeeper, checking identities. And authorization uses an access token to decide what you are allowed to do based on that verified identity. Authentication independently verifies who you are without relying on authorization, but authorization depends on authentication to grant appropriate access and permissions.

Authentication and Authorization, putting it into practice.

Authentication and Authorization are two pillars that protect the security of your app, as well as safeguarding your users and their data. These processes have significantly evolved. As a developer, you must stay informed about the latest and most secure methods. Key methods include multi-factor authentication, using security tokens, and verifying identities on mobile phones through biometrics and other authentication factors.

You can find detailed coding examples and more by exploring the following articles:

Additionally , If you want to make a good user experience, read our guide on Mastering signup systems.

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