4 ms·
Since there are 180million of them, presumably they were generated with a computer. Then, it seems that they probably fit into a finite number of patterns. If t
by moxiemk1 16y ago
Since there are 180million of them, presumably they were generated with a computer. Then, it seems that they probably fit into a finite number of patterns. If these could be determined, wouldn't this be a rather easy to crack captcha system?
Most captchas depend on the difficulty of the reverse transform applied to an image, especially when you don't know what the transform is. Here, the forms seem pretty regular, and the "transform" of inserting words is discrete rather than continuous, so a bit easier to reverse.
- mseebach 16y agoIt will only be little harder to reverse than it was to develop. Unless the generation of patterns can be distributed to attain a scale that the attackers can't match, this will fail as soon as it's protecting something worthwhile.
- mike-cardwell 16y agoYeah, the 180million number is irrelevant. What's important is the number and variety of patterns, not the number of questions. I don't even need to program something which will understand all of the patterns. I just need to program something that will understand some of the patterns, which just keeps fetching captchas until it eventually understands the format, eg "What is X plus Y?" This captcha system is considerably more simple to break than the typical image based ones.
- ryanc 16y agoNot only do they follow a small number of patterns, most that involve subject matter rather than simply logic are part of a small number of categories. Almost all involve body parts, colors, names and days of the week.