A method of authenticating a user. The method comprises the step of sending an authentication request to a remote authentication device and generating a first piece of authentication information. A mobile device receives the first piece of authentication information from either an access terminal or the remote authentication device. The mobile device of the user generating a second piece of authentication information which is at least partially based on the received first piece of authentication information. The second piece of authentication information is sent to the remote authentication devices and the second piece of authentication information validated. If the second piece of authentication information is successfully validated an authentication signal is generated.