A mechanism to improve the security and access control over a network, such as a wireless local area network (“WLAN”), that takes advantage of web browser interactions without requiring explicit separate communication session between a hot spot network and a service provider network. The method comprises receiving a request to access the WLAN from a mobile terminal (MT)/client disposed within a coverage area of the WLAN. The access point (AP) of the network associates a session ID and randomized number with an identifier associated with the MT and stores data mapping the session ID to the identifier of the MT and randomized number. The local server transmits an authentication request in the form of a web page, which includes the session ID and randomized number, to the MT. The AP receives from the MT a digitally signed authentication message, a parameter list containing user credential information, session ID, and randomized number concerning the MT, the authentication message being digitally signed using the session ID and randomized number together with the parameter list. The AP correlates the session ID and parameter list received from the MT and, using the stored mapping data, generates a local digital signature for comparison with the received digitally signed authentication message for controlling access of the MT to the WLAN.