ietf-openpgp
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Re: NIST publishes new DSA draft

2006-03-14 15:01:23

We might want to think about making SHA-256 be another MUST algorithm.
The only MUST hash now is SHA-1.  Making SHA-256 be a MUST would make
these new key sizes be more useful, and also give us an easier fallback
if SHA-1 should be broken.

SHA-1 was broken, last month by three Chinese cryptographers as reported 
by Bruce Schneier through is website.  On February 15, 2006 he wrote of 
a new cryptographic result, an attack faster than brute-force against 
SHA-1.  Two days later he wrote an update to his original post and a 
quote from within it:

Earlier this week, three Chinese cryptographers showed that SHA-1 is not 
collision-free. That is, they developed an algorithm for finding collisions
faster than brute force.

...

They can find collisions in SHA-1 in 2^69 calculations, about 2,000 times
faster than brute force. Right now, that is just on the far edge of 
feasibility with current technology. Two comparable massive computations 
illustrate that point.

Reference URL (02/18/2006): http://tinyurl.com/4rl78
Original post (02/15/2006): http://tinyurl.com/4bmcc

With respect to your suggestion about thinking about making SHA-256 a MUST 
algorithm I couldn't agree more.

Cheers,

James

-- 
James Couzens,
Programmer
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