Jonathan's comment brings up the importance of the difference between authentication and identification. Authentication really only requires proving access, while identification requires proving that you are a given person, which goes to show that you have access. It is perfectly easy to remove the step in a given system of needing to determine which human being is the one requesting access. For example, E*TRADE hands out these RSA key generators when you sign up for an account; such a device could easily be employed with a bank account if people thought them secure enough. The point about identification vs. authentication is crucial though; people are trained to assume that identities are proof of something when it is the right of access that is important.

-- RickSchwartz - 27 Feb 2009