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Security Review Summary of NIST SHA-3 Round 1
FormOfActionBanana writes "The security firm Fortify Software has undertaken an automated code review of the NIST SHA-3 round 1 contestants (previously Slashdotted) reference implementations. After a followup audit, the team is now reporting summary results. According to the blog entry, 'This just emphasizes what we already knew about C, even the most careful, security conscious developer messes up memory management.' Of particular interest, Professor Ron Rivest's (the "R" in RSA) MD6 team has already corrected a buffer overflow pointed out by the Fortify review. Bruce Schneier's Skein, also previously Slashdotted, came through defect-free."
Why do they even have a reference implementation for a hash function in a programming language? Wouldn't just defining the function mathematically be less error prone and just as effective?
Yeah, both very good points.
People do make mistakes. Even geniuses, when they're trying really hard to be careful. Personally, I see recognizing that as a validation for code review (including the automated code review that I do).
I want the winning entry for this competition to be flawless to the extent that's feasible. Right now, my job includes finding SHA-1 for cryptographic key generation, and telling people to replace that with something better. I don't want to be pulling out SHA-3 in a couple years, too.
Take off every 'sig' !!
But that just raises the question of how to define a hash function mathematically? The lambda calculus, Godel Numbers? Things like cryptographic hash functions don't tend to be nice algebraic thingies like f(x)=x*x+7, especially since they're usually iterative and deliberately messy - the pretty functions are likely to be less secure.
On the other hand, there are things like cryptol in which you may be able to specify hash functions more mathematically. For example, here is a cryptol implementation of skein.