SHA-1han been broken.

http://www.schneier.com/blog/archives/2005/02/sha1_broken.html

SHA-1 has been broken. Not a reduced-round version. Not a simplified
version. The real thing.

The research team of Xiaoyun Wang, Yiqun Lisa Yin, and Hongbo Yu (mostly
from Shandong University in China) have been quietly circulating a paper
describing their results:

- collisions in the the full SHA-1 in 2**69 hash operations, much less
than the brute-force attack of 2**80 operations based on the hash length.

- collisions in SHA-0 in 2**39 operations.

- collisions in 58-round SHA-1 in 2**33 operations.

This attack builds on previous attacks on SHA-0 and SHA-1, and is a major,
major cryptanalytic result. It pretty much puts a bullet into SHA-1 as a
hash function for digital signatures (although it doesn't affect
applications such as HMAC where collisions aren't important).

The paper isn't generally available yet. At this point I can't tell if the
attack is real, but the paper looks good and this is a reputable research
team.

More details when I have them.


ciao,
gaetano


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