Dan Swall

Authentication is the process of determining what you are allowed to do a user. My Favorite form of authentication is Biometrics, or the body measurment method. 

I like biometrics a lot because it's especially difficult to fake them. The reasoning behind this is, beyond actually lobbing off someone's finger or going through all the effort of making a gelatin mold of it or ripping out someone's eyeball, it's nearly failproof. Compared to something else like a password which can be intercepted in any manner of ways, or a smart card that can be stolen, biometrics are nearly flawless in their ability to be screwed up. It's really hard to forget your fingerprint on the way to work one day (smart card) or forget what it is (password). Failing fingerprints, I consider retinal scans to be the most accurate and tamper-proof method of authentication, as far as the biometrics aspect is concerned.

To make finger printing more secure, instead of a sensor that just reads the lands and falls of your finger, I would add capacitance sensing to ensure you're scanning with real flesh and blood instead of just waving a gelatin finger across. A DNA sequencer would also be a pretty fool-proof way to prove who you are.