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Cryptography Expert Sounds Alarm At Possible Math Hack
netbuzz writes "First we learn from Bruce Schneier that the NSA may have left itself a secret back door in an officially sanctioned cryptographic random-number generator. Now Adi Shamir is warning that a math error unknown to a chip makers but discovered by a tech-savvy terrorist could lead to serious consequences, too. Remember the Intel blunder of 1996? 'Mr. Shamir wrote that if an intelligence organization discovered a math error in a widely used chip, then security software on a PC with that chip could be "trivially broken with a single chosen message." Executing the attack would require only knowledge of the math flaw and the ability to send a "poisoned" encrypted message to a protected computer, he wrote. It would then be possible to compute the value of the secret key used by the targeted system.'"
TFA is just a summary of an article yesterday in the NYT: http://www.nytimes.com/2007/11/17/technology/17code.html?ref=technology
In the past there have existed implementations of integer math that used the floating point unit. The only one I know of off hand is the Prime95 Mersenne prime search program. I imagine there are others, though. The reason for this is simply that the floating point units were faster -- more bits per operation. The x87 FPU instructions operate on 80 bit floating point numbers, compared to 32 bit integers (the floating point numbers can't use the exponent bits, but it's still more than 32 by a lot). If your code is sufficiently parallel, and you put forth the effort, there was a performance gain to be had. I don't know if this is still the case in modern CPUs (especially 64 bit ones), but it's entirely possible to do high-performance integer math on the floating point unit.