On Mon, 13 Feb 2006 07:09:48 +0100, php0t said: > the global solution against word recognition based challenges? If it was > like that, it would mean that there is no way anybody could make an > image generator that would change its success rate from 90% to 0%... It's *really* *really* difficult to produce a graphic image of letters and numbers that is still recognizable to a human but can't be beaten by a good edge-detection algorithm. For instance, you can "bleed" the edges so that they're fuzzy - but then the human has a hard time telling if it's an 'i' or an 'l', or an 'h' or a 'b' (and so on). I suppose you *could* put up a picture of something, and ask "What is this a picture of" - but then you need a sufficiently large library of images that an attacker can't just download all of them and have a human name each one once. And of course, this has the danger that a user can be left saying: "WTF? Is that an antelope or a gazelle?"....
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