On Tue, Dec 07, 2004 at 06:51:48PM -0700, Joel Maslak wrote: > That can be a problem. It breaks non-repudiation - someone could create > such a "swappable" contract and go to court and say "Yes, that's a valid > signature, but I really signed *THIS* document which just happens to have > an identical signature." Of course if I was called upon to testify, I > would respond, "Yes, but it is clear this contract was written with the > intent to defraud us, as to get this property, it has to be constructed in > a very specific mind with this fraud in mind at time of contract > origination..." Bruce Schneier has long suggested that when signing a document made by others, make some cosmetic changes to break any precomputed hash that the creator might have in store for you. Also: those who are not fully up to speed on the details of crypto hashes might find my Tech Tip helpful: An Illustrated Guide to Cryptographic Hashes http://www.unixwiz.net/techtips/iguide-crypto-hashes.html Steve -- Stephen J Friedl | Security Consultant | UNIX Wizard | +1 714 544-6561 www.unixwiz.net | Tustin, Calif. USA | Microsoft MVP | steve@xxxxxxxxxxx
