A method of authentication and accessing resources is provided. A client device may send a request to a proxy device to access a resource, such as an enterprise resource. The proxy device may authenticate with one or more servers associated with the resource. During authentication, the proxy device may receive a request for a signature controlled by the client device. In response, the proxy device may send a request to the client device for the signature. The request may also include context information that identify a data structure of authentication information exchanged (or to be exchanged) during the authentication session. If the client device verifies the context information, the client device may send the requested signature.