AUTHI is an image based personalized authentication service.
First of all, when a user registers on a site or service running AUTHI, they are asked for a very simple passcode. Like really simple. Like "popcorn" or something.
Next they are presented a slew of images representing common things that people often have feelings about. Like food, cars, cities, or fictional creatures. AUTHI then asks the user to rifle through its vast library of imagery and find things that they either REALLY LOVE or REALLY HATE. Once AUTHI has enough data, it compiles it down into a secret key.
When the user comes back to the site or service running AUTHI, they must provide their passcode and are presented with a bunch of images and again asked to let AUTHI know which ones they REALLY LOVE or REALLY HATE. If they get even a single choice wrong, AUTHI will reshuffle and present new options although it won't tell them which ones were right or wrong. If it still doesn't work after a few tries, AUTHI will lock them out until they can authenticate via email.
In other words, people can get access to sites and services just by knowing themselves. The collection of data is intended to be large enough that you would have to know a person extremely well to act like you are them.