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| Subject: | RE: MD5 Collisions and Evidence Integrity |
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| Date: | Mon, 15 Nov 2004 20:33:58 +0100 |
Even worse, if the alteration was intentional, there's known *fast* algorithms for creating a new plaintext with the same CRC-32. Basically, you use the same algorithm that is used for *every single* packet transmitted on the Internet, as specified in RFC1141/1624. I don't know of any routers that *don't* update the IP checksums in hardware.
Exactly my point. The reason for using hashing in computer forensics is to be able to prove that that the evidence is unchanged; intentional or unintentional. If it is possible to make intentional changes and still end up with the same hash sum, then the algorithm is too weak. As stated in my previous post, I do not think MD5 is there yet. -- Svein Y. Willassen, M.Sc. Special investigator, Norwegian National Computer Crime Center ----------------------------------------------------------------- This list is provided by the SecurityFocus ARIS analyzer service. For more information on this free incident handling, management and tracking system please see: http://aris.securityfocus.com
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