A system and associated method for providing enhanced site access security by use of multiple authentications from independent sources. A security enhanced user service system has components of a user authentication process, a service application, a multi-authentication module and an authentication database. A user attempting to use the service application accesses through a client system that is coupled to the security enhanced user service system. The user authentication process receives login information from the user, checks for validity, and sends to the multi-authentication module to further verify the login information. The multi-authentication module generates a grant or denial by use of predefined logical condition to satisfy for the grant response, data stored in the authentication database, another security enhanced user service system etc., pursuant to a specific configuration.