Re: MD5 & bot Question
| From: | tedd | Date: | Mon, 09 Apr 2007 21:14:55 +0000 |
| Subject: | Re: MD5 & bot Question | ||
| References: | 1 2 3 4 5 6 7 8 9 10 11 12 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-252366@lists.php.net to get a copy of this message | ||
At 4:39 PM -0400 4/9/07, Robert Cummings wrote:
On Mon, 2007-04-09 at 22:27 +0200, Tijnema ! wrote: This is exactly what tedd did in his last arrow example. He edited theRob: It doesn't need to be complicated, just random placed pixels on the image from a selection of colors would provide millions of permutations. Cheers, tedd -- ------- http://sperling.com http://ancientstones.com http://earthstones.comheader of the GIF image, and so that would result in different MD5. Finding this part and skipping it in the MD5 check would do the job. :)Yep, that's an obvious solution since it's the same way virus signatures are matched. The entire image needs some kind of permutation. Passing a couple of curved ripples across the image as a transformation, and in different directions should suffice to obfuscate the image signature without obfuscating the image itself :) Similarly watermarking the image using fractal patterns should also provide good noise. Cheers, Rob.