Re: Whirlpool 512-bit collisions?

Matt Mahoney wrote:
> (1) most certainly does have collisions for most of the possible 512
> bit inputs. It is not a big security risk because the probability is
> only 2^-512 for any pair of inputs.

Often hash functions are used to "whiten" bits collected from an entropy
source. Since there are collisions, entropy is lost by hashing. (eg You
might put 512 bits of entropy in, but how much entropy is in the output?
Less than 512 bits if there are collisions) It would be useful to have
some measure of how much entropy is lost when hashing.

Alan
Received on Thu Sep 29 21:43:59 2005