[Python-Dev] Algoritmic Complexity Attack on Python (original) (raw)

Guido van Rossum guido@python.org
Fri, 30 May 2003 20:41:54 -0400

+ If I understand what you're selling, the hash code of a given string will almost certainly change across program runs. That's a very visible change in semantics, since hash() is a builtin Python function available to user code. Some programs use hash codes to index into persistent (file- or database- based) data structures, and such code would plain break if the hash code of a string changed from one run to the next. I expect the user-visible hash() would have to continue using a predictable function.

Of course, such programs are already vulnerable to changes in the hash implementation between Python versions (which has happened before).

--Guido van Rossum (home page: http://www.python.org/~guido/)