the cool thing about stuff like this (I am familiar with a few different efforts along this vein) is that you can combine something you are with something you k

the cool thing about stuff like this (I am familiar with a few different efforts along this vein) is that you can combine something you are with something you know. the downside of fingerprints and retinas is they can be passively recorded and replayed, but with the brain, you could build an authenticator that only works when the user is cooperating with the authentication scheme, and, recording and replaying the electrical signal from the brain won't spoof the authenticator. until you really refine the task down to take a few seconds and you have dry cap electrodes, it's still untenable, but progress has been made on the latter.