Need secure login

Hi, I have a client. He does not want member login by just giving password and login id. He says anybody can give this info to his friend and his friend can access the site. One way is to make use of cookie on his computer. So only from one computer he can access the site. But the thing is that user needs to accept it, and i believe I need to provide some method too in case they delete the cookie. Is there any other solution for this ? Is there any third party software for this ? Regards Manisha