How OAuth Tokens Work and Implementing them in Your Application

What Is an OAuth Token?

OAuth, or Open Authorization, is an open-standard authorization protocol that allows third-party applications to gain access to user data without exposing their password.

An OAuth token is a unique string of characters that authenticates a user or app on a network without requiring them to share their password. It’s like a digital passport, granting permissions and access rights. In essence, an OAuth token is a secure method of proving your identity or the identity of an application to a server.

In this article:

• The Role of Tokens in the OAuth Protocol 
• Types of OAuth Tokens 
  • Access Tokens
  • Refresh Tokens
• How OAuth Tokens Work 
  • Tokens are Generated by the Authorization Server
  • Tokens are Requested and Received by the Client
  • The Lifecycle of an OAuth Token
• Implementing OAuth Tokens in Your Application 
• Using OAuth with Frontegg

The Role of Tokens in the OAuth Protocol 

Tokens play a significant role in the OAuth protocol. They act as a substitute for the user’s credentials, ensuring their password remains confidential while still allowing the server to verify their identity.

The primary purpose of an OAuth token is to facilitate secure access to user data. When a third-party application requests access to a user’s data, the server issues an OAuth token. This token allows the application to access the data without needing the user’s password.

Tokens provide an additional layer of security in the OAuth protocol, because they limit the amount of time an application has access to a user’s data. Once the token expires, the application must request a new one, providing a continuous check on the app’s access.

Types of OAuth Tokens 

Access Tokens

Access tokens are the most commonly used type of OAuth tokens. They are used to access protected resources on behalf of the user. Access tokens are short-lived, usually expiring after a few hours.

The advantage of access tokens is that they limit the potential damage if they are stolen. Since they are short-lived, a stolen access token will soon become useless. They also allow the server to verify the identity of an application or user without needing to store their password.

Two types of access tokens are Bearer Tokens and MAC Tokens: 

• Bearer tokens can be used by any entity (the bearer) that possesses the token, with no additional proof of identity required. This requires additional security measures, to avoid attackers making use of stolen bearer tokens. 
• MAC (Message Authentication Code) tokens add an extra layer of security by requiring the client to include a unique cryptographic signature with each request. The signature is derived from the token secret, which is not transmitted with the request, making it more secure against interception or theft.

Refresh Tokens

In contrast to access tokens, refresh tokens are long-lived. They are used to obtain a new access token when the current one expires. Refresh tokens are stored securely on the server and are only sent over the network when necessary.

Refresh tokens provide an additional layer of security. If an attacker manages to steal an access token, they will not be able to obtain a new one without also stealing the refresh token.

Learn more in our detailed guide to OAuth grant types

How OAuth Tokens Work 

Understanding how OAuth tokens work involves understanding how they are generated, requested, and received, as well as their lifecycle.

Tokens are Generated by the Authorization Server

The first step in the OAuth process is for the application to request authorization from the user. The user logs in to the server and grants the application permission to access their data.

Once the user grants permission, the server generates an OAuth token. The token is a unique string of characters that represents the permissions granted by the user.

Tokens are Requested and Received by the Client

When a user attempts to access an application, it requests the OAuth token from the server. The server sends the token to the application in a secure, encrypted format.

The application stores the token and uses it to make requests to the server on behalf of the user. Each time the application makes a request, it includes the token. The server verifies the token and, if it is valid, processes the request.

The Lifecycle of an OAuth Token

The lifecycle of an OAuth token begins when it is generated by the server and sent to the application, which stores it and uses it to make requests.

The token remains valid until it expires. The server determines the token’s lifespan when it generates the token. Once the token expires, the application must request a new one.

If the user revokes the application’s access, the server invalidates the token immediately. The application can no longer use the token to make requests.

Learn more in our detailed guide to OAuth refresh token (coming soon)

Implementing OAuth Tokens in Your Application 

Implementing OAuth tokens requires careful planning and consideration. You need to ensure your application securely stores the tokens and handles them correctly:

1. When implementing OAuth tokens, you first need to set up the server to generate and verify tokens. This involves configuring the server to use the OAuth protocol and setting up the necessary encryption and security measures.
2. Modify your application to request tokens and use them to make requests. This involves adding code to your application to handle the OAuth process, including requesting and receiving tokens, storing them securely, and including them in requests.
3. Ensure your application handles token expiration and revocation correctly. The application should check the token’s validity before making a request. Additionally, it needs to recognize if the server rejected a request because the token has expired or been revoked.

Using OAuth with Frontegg

Frontegg’s end-to-end and self-served authentication infrastructure is based on JSON Web Tokens. Our JWTs have been designed to adhere to the highest security standards. Therefore, our user management solution is also fully compliant with the OAuth protocol, along with OpenID Connect 1.0 (OIDC) as well. We cover all important bases that are required in the modern SaaS space. 

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