http://www.lightbluetouchpaper.org/2012/05/22/the-quest-to-replace-passwords/
The quest to replace passwords
As any computer user already knows, passwords are a usability disaster: you are basically told to “pick something you can’t remember, then don’t write it down“, which is worse than impossible if you must also use a different password for every account. Moreover, security-wise, passwords can be shoulder-surfed, keylogged, eavesdropped, brute-forced and phished.
Why? Can’t we do any better? Don’t the suggested replacements offer any improvements?
We build a large 2D matrix. Across the columns we define a broad spectrum of 25 benefits that a password replacement scheme might potentially offer, starting with USABILITY benefits, such as being easy to learn, or not requiring a memory effort from the user, and SECURITY benefits.