Re: MD5 & bot Question
| From: | tedd | Date: | Tue, 10 Apr 2007 19:53:24 +0000 |
| Subject: | Re: MD5 & bot Question | ||
| References: | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | Groups: | php.general |
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At 1:17 PM -0400 4/10/07, Robert Cummings wrote:
-snip- That should have read: "... since no subset of..."Oh well, now it makes sense ! :-) Actually, I see exactly what you are saying. If you take a small portion of a file and MD5 it, it will give you a signature. If I simply change a single pixel in the image and that pixel is NOT included in the small portion you use for your MD5, then the MD5 check will return the same signature as before the alteration. However, if your portion includes the pixel change, then the resultant MD5 will be different. That's the reason why you need to alter a significant portion of the image so that smaller portions will probably contain some alteration. Thanks for explaining that. tedd -- ------- http://sperling.com http://ancientstones.com http://earthstones.com