Re: MD5 & bot Question

On Mon, 2007-04-09 at 17:14 -0400, tedd wrote: > 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 the > >> header 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. > > Rob: > > It doesn't need to be complicated, just random placed pixels on the > image from a selection of colors would provide millions of > permutations. No, you're wrong. Read the part about I mentioned about virus signatures. A small portion of the whole can be used as an identifier where that portion is unique to the overall entity. For instance, I can throw a tub of tar over you, then a tub of feathers ;) ;) and if one of your fingers doesn't get covered, I can still identify your chicken ass ;) Cheers, Rob. -- .------------------------------------------------------------. | InterJinn Application Framework - http://www.interjinn.com | :------------------------------------------------------------: | An application and templating framework for PHP. Boasting | | a powerful, scalable system for accessing system services | | such as forms, properties, sessions, and caches. InterJinn | | also provides an extremely flexible architecture for | | creating re-usable components quickly and easily. | `------------------------------------------------------------'