The present disclosure describes techniques that improve upon the use of authentication tokens as a means of verifying a user identify. A server is described that receives a service request to access a secure service provided by another service provider. The server may determine whether an additional secure service is required from a third-party server, and if so, generate a recursive authentication token for delivery to the third-party server. The recursive authentication token is intended to authenticate an identity of the server to the third-party server.