An authentication system may receive a request signature corresponding to a user request to view secure user information on a user device and generate a server-side signature matching the request signature to authenticate the user device to receive the secure user information without authenticating the user. The request signature may include a device identifier corresponding to the device, a token code generated by the authentication system and stored by the user device, a timestamp corresponding to the transmission time of the request signature, and a version of the device identifier, the token code, and the timestamp encrypted using a signature key provided to the user device by the authentication system. The authentication system may generate the server-side signature using the timestamp and stored copies of the device identifier, the token code, and the signature key.