In the Web application space, access control is almost always an immediate result of a successful user login. The question is whether knowledge of a certain website password entitles a user to get access to a financial, healthcare, or some other site. Would your bank ever trust that the some-other site did enough checking on a customer's identity to enable a successful login? And if that is not the case, then how many passwords are we going to have to remember?
It is good to remember that everything we might be able to assert on a user identity is a point on a continuum: There really is no black and white here. So until access control is done correctly in Web applications, I believe that most of the websites will have to provide somewhat separate authentication criteria.
Recognized in the industry as the "inventor of SSL," Dr. Taher Elgamal led the SSL efforts at Netscape. He also wrote the SSL patent and promoted SSL as the Internet security standard within standard committees and the industry. Dr. Elgamal invented several industry and government standards in data security and digital signatures area, including the DSS government standard for digital signatures. In addition to serving on numerous corporate advisory boards, Dr. Elgamal is the Chief Security Officer at Axway, a global provider of multi-enterprise solutions and infrastructure. He holds a Ph.D. and M.S. in Computer Science from Stanford University. View more of his blog posts here.