Oppfriskningstokens

Oppfriskningstokens, also known as refresh tokens, are a crucial component in modern authentication systems, particularly within the OAuth 2.0 framework. Their primary purpose is to allow clients to obtain new access tokens without requiring the user to re-authenticate every time an access token expires. Access tokens are typically short-lived for security reasons, meaning they have a limited validity period. If an application were to solely rely on access tokens, users would frequently be prompted to log in, creating a poor user experience.

Refresh tokens solve this problem by acting as a long-lived credential. When a client application receives an initial set of tokens, it usually receives both an access token and a refresh token. The access token is used to make API requests on behalf of the user. When the access token expires, the client can present the refresh token to the authorization server. The authorization server then validates the refresh token and, if valid, issues a new, short-lived access token. This process allows for continuous access to resources without repeated user interaction.

The security of refresh tokens is paramount. They are typically generated by the authorization server and should be stored securely by the client application. If a refresh token is compromised, an attacker could potentially obtain new access tokens indefinitely. Therefore, mechanisms such as rotating refresh tokens, limiting their scope, and implementing revocation policies are often employed to mitigate these risks. The use of refresh tokens strikes a balance between user convenience and the necessary security measures in delegated authorization.