[Python-Dev] Status of the fix for the hash collision vulnerability

[Guido van Rossum]

On Fri, Jan 13, 2012 at 9:08 AM, Mark Dickinson <dickinsm at gmail.com> wrote:

> On Fri, Jan 13, 2012 at 2:57 AM, Guido van Rossum <guido at python.org>
> wrote:
> > How
> > pathological the data needs to be before the collision counter triggers?
> I'd
> > expect *very* pathological.
>
> How pathological do you consider the set
>
>   {1 << n for n in range(2000)}
>
> to be?  What about the set:
>
>   ieee754_powers_of_two = {2.0**n for n in range(-1074, 1024)}
>
> ?  The > 2000 elements of the latter set have only 61 distinct hash
> values on 64-bit machine, so there will be over 2000 total collisions
> involved in creating this set (though admittedly only around 30
> collisions per hash value).
>

Hm... So how does the collision counting work for this case?

-- 
--Guido van Rossum (python.org/~guido)
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