=== OAuth token compromise The OAuth 2.0 authorization code grant flow is a secure method of authorizing a web application to access a third-party service. After the user authenticates with the third-party service and grants access, the web application is sent a single-use code. The application must then pass this code and a `client_secret` value to the service in order to obtain a usable authentication token. If the `client_secret` value is disclosed, anyone who can intercept the single-use code can then exchange it for a valid authentication token.