SHA-256/384/512 Released

The Right Brute writes "It appears that the successors to the SHA-1 cryptographic digest algorithm have been released. FIPS 180-2 can be found here which I believe is the final version of the SHA-256/384/512 algorithm (it does not appear to have changed since the last draft). I have an implementation that I did as a CWEB literate programming example that might serve as a good companion to the specification."

Comments

Re:Algorithm Flaw

[amorsen]

The entire thing that got me started, was a downloaded Slackware ISO from an unofficial mirror, that had the correct checksum, but was hopelessly corrupt due to transmission errors close to my side. There was enough change in the ISO that by fluke chance, the MD5 checksum was identical. That is already a 512 bit checksum that was defeated, albeit in-advertantly.

The MD5 checksum is 128 bit, not 512 bit. Weaknesses have been shows in it, but so far noone has been able to produce two files with the same MD5 checksum. If you have the corrupted ISO with the same checksum, you have the chance to become famous. Until I see proof I will remain rather sceptical.

Oh and about the 384 bit checksum made from a 512 bit checksum, yes of course the 384 bit checksum is weaker. Otherwise people would use it all the time. There is no reason to think that it is any weaker than a checksum giving 384 bit directly, though. It is believed that if you chop off half of the output bits of SHA-160 (the old SHA) you will have an 80-bit checksum with no weaknesses except for brute force.