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

Mark Dickinson dickinsm at gmail.com
Fri Jan 13 18:08:26 CET 2012

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).


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