Md5's time has come and gone.

Question

--MD5 Hashing Algorithm Flawed
(28 January 2005)
Security researchers are warning that the MD5 hashing algorithm, which
is used by two of the three major content addressed storage system
vendors, is flawed.  MD5 has reportedly been decertified for secure
operations by NIST since at least 1998.
http://www.computerworld.com/printthis/ … 31,00.html
[Editor's Note (Tan): So far the MD5 collision is only on two 1024-bit
messages (http://eprint.iacr.org/2004/199.pdf), but this is sufficient
to prove that it is not 100% reliable. It will be good to start
considering using a larger hash function. In fact, NIST plans to phase
out SHA-1 in favor of SHA-224, SHA-256, SHA-384 and SHA-512 by 2010
(http://csrc.nist.gov/hash_standards_comments.pdf).
(Schneier): As the article says, the idea that there are flaws in MD5
is nothing new.  It really is time and past for vendors to stop using
it.]
from: SANS NewsBites--Feb. 2, 2005--Vol. 7, Num. 5
I realize that I am Mr. Security-Nutcase-stickler-uptight, but I think arch should move away from md5 towards SHA-256. md5 has been known to not be cryptographically secure for some time now. I think steps should be taken for migration...

Answer 1

extra length does not necessarily ensure a better hash.
Hashing algorithms are big voodoo, lots of "tricks" to try to chop down to the bits specified.
Anyway, back to your statement. md5 outputs a 128 bit hash result. sha1 outputs a 160 bit result. md5 has been shown to have collisions. sha1 has so far not (the full 80 round version. A simplified 30 round version was shown to have some weakness).
Sha1 can address...
*counts on fingers*
2^160..
according to the "birthday" algorithm (heh..that is the only way I can remember it) you would only need approx 2^80 to find a collision (half the address space).
sha-256 is of course, a 256 bit outputting hash.
So with sha-256 (if it is "secure", and so far it appears to be so), you would need..
2^128...aka a big damn number.
That is, of course, if you are simply doing exhaustive searches for collisions. I believe there was some issue with md5, some trick if you will, that allowed them to theoretically reduce the address space further than 2^64.
But, as I said, this is likely a non-issue for a couple more years. Still, it would be nice to be the first distro to move off of md5, because eventually, everyone will have to do so.