Authorization Code Flow

A secure method for obtaining an access token in Single Sign-On (SSO) systems.

Description

Authorization Code Flow is a widely adopted method in the Single Sign-On (SSO) industry, particularly used in OAuth 2.0 protocols. It is designed to ensure that user credentials are not exposed to third-party applications while allowing users to authenticate via an identity provider. The process begins when a user attempts to access a client application. The application redirects the user to the identity provider's authorization server, where they log in. Upon successful authentication, the server redirects the user back to the client application with an authorization code. This code is then exchanged for an access token by the client application by making a secure request to the authorization server. This flow provides a high level of security, as the access token is never exposed in the browser and is transmitted directly between the client and the server. Additionally, it can also support refresh tokens, allowing for a seamless user experience without requiring repeated logins.

Examples

  • Google's OAuth 2.0 implementation allows users to log into third-party applications using their Google account through the Authorization Code Flow.
  • Microsoft Azure Active Directory uses the Authorization Code Flow to enable users to access various services like Office 365 with a single login.

Additional Information

  • The Authorization Code Flow is particularly useful for server-side applications where security is paramount.
  • This flow helps prevent attacks such as authorization code interception, as the authorization code is exchanged server-to-server.

References