A Refresh Token is a credential used in Single Sign-On (SSO) systems to obtain a new access token without requiring the user to log in again.
Description
In the context of Single Sign-On (SSO) protocols, a Refresh Token is a special kind of token that is issued to the user after they authenticate successfully. Unlike access tokens, which have a limited lifespan and are used to access protected resources, refresh tokens are long-lived and can be used to request new access tokens without needing user credentials again. This enhances user experience by allowing seamless access to applications without repeated logins. For instance, when a user logs into their Google account, they receive both an access token and a refresh token. If the access token expires after a short period, such as one hour, the application can use the refresh token to request a new access token. This process is crucial for maintaining secure sessions while minimizing user disruption. Refresh tokens also help in securing sensitive information by reducing the frequency of credential transmission across the network.
Examples
- Google uses refresh tokens to allow users to continue using their services, like Gmail, without needing to log in repeatedly.
- In OAuth 2.0, many APIs, such as those from Facebook, provide refresh tokens to maintain user sessions for mobile applications.
Additional Information
- Refresh tokens should be stored securely, as their compromise can lead to unauthorized access.
- The usage of refresh tokens is governed by specific expiration policies, which can vary by application and ensure security.