[SM-Discuss] Compromise on signatures
Sergey A. Lipnevich
sergey at optimaltec.com
Tue Aug 30 23:53:48 EDT 2005
Quoting Seth Alan Woolley <seth at positivism.org>:
> Adding a length to a hash outside the hash is one more level of
> difficult for an attacker attempting to use massive appends to gain a
> collision (which is a totally different way than the technique above).
> Sergey is trying to prevent:
> sfsfasdfs = 46643
> sfsfasdfsfsdfasdfamaliciouscodefsdfsdfadfd = 46643
> Completely different problem.
Yes, that's what I meant. Using "massive append" would be impossible if we
include the length. However, what I don't know is what's the easier way
a collision: looking for different data of the same length, or
appending/removing data. If the latter is a trivial task, we will improve the
chances against hash collision significantly. But if collision by
appending/removing bytes is difficult, we're not going to gain much
> See extract from the article you already linked to :):
I should read this article...
More information about the SM-Discuss