Re: MD5 To Be Considered Harmful Someday

[Paul Wouters <paul@xxxxxxxxx>]

On Wed, 8 Dec 2004, Dan Kaminsky wrote:

> > Can't we just truncate the password to 8 characters like in the old days
> > before doing the MD5 hash? It will greatly reduce the chance of a 
> > collision.
> > In fact, I am not even sure my systems don't do this already.
> Actually, this greatly increases the chance of a collision.  123456789 will 
> collide with 123456780.

I was talking about limiting the input, not the output. I assumed it would
be more difficult to find a collision when there are less degrees of freedom
in the input.

What I realised after my mail though, is that it is probably pretty easy to
prebuild a dictionary of all 8 character combinations and their MD5 sums.

Paul