Using SHA1 as RNG

Klaus Alexander Seistrup spam at
Fri Mar 14 21:03:25 CET 2003

Giovanni Bajo wrote:

> Python 2.3 will use the Marsenne-Twister RNG, whose period is
> 2^19937-1. Big enough I'd say. It's also faster to calculate.

Thanks for bringing the good news.  Yes, 2^19937-1 it big enough
for me. :)

>> So I thought, why not use SHA1 in the core generator?
> Unless you studied the distribution, you have no proof that the
> resulting sequence has a long period, for any starting seed.

Yes, you are right.  Irmen de Jong also pointed out this serious

> And besides, it would probably be very slow.

It's not too bad, as the SHA1 modules is written in C.  However,
since I don't know anything about the distribution of numbers
within a SHA1 sequence, I'm probably better off waiting for the
Mersenne Twister to reach my Python interpreter.

Thanks for your feedback.

  // Klaus

 ><> 	unselfish actions pay back better

More information about the Python-list mailing list