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It's been tried: google "kittenauth". The problem is that you need to collect the images from somewhere, so the keyspace is too small.
by dfranke 17y ago
It's been tried: google "kittenauth". The problem is that you need to collect the images from somewhere, so the keyspace is too small.
- patio11 17y agoRight, but for kittenauth you need to "burn" 9 images to achieve one authentication. (Three kitties and six non-kitties, as I recall correctly.) With the rotational thing, a single source image can be algorithmically manipulated to generate dozens or hundreds of challenges -- kitty at a 90 degree angle to the left, kitty at a 90 degree angle to the right, etc. Figuring that, conservatively, you can get a dozen challenges out of an image, that makes this technique about a hundred times more efficient than kittyauth in terms of how many challenges you can issue for the size of your library. Then you pair it with a large set of images (cough Flickr Creative Commons license cough) and you're off to the races. (The Flickr Creative Commons option isn't abused to nearly its potential by startups.)
- dfranke 17y agoI'm not a CG guy, but I'm guessing it's pretty simple and efficient to recognize which of a set of images a given image is a rotation of. So the ability to create lots of rotations doesn't buy you any security.