Authority transfer system, control method of authorization server, authorization server and program

摘要

An authorization delegation system includes a resource server that provides a service and an authorization server that performs authorization delegation for authorizing a cooperation server, which is a client apparatus, access to user data that the resource server has based on authorization information. The authorization server receives an authorization delegation request for requesting the authorization delegation, and retrieves a refresh token based on the received authorization delegation request. Additionally, the authorization server determines whether or not the retrieved refresh token is valid, and if it is determined that the refresh token is valid, invalidates the refresh token.