Internal states..

ryan10975073 at netscape.net ryan10975073 at netscape.net
Wed Sep 10 04:51:35 CEST 2003


Chad Netzer <cnetzer at sonic.net> wrote:

>On Tue, 2003-09-09 at 19:05, ryan10975073 at netscape.net wrote:
>> Chad Netzer <cnetzer at sonic.net> wrote:
>
>>   Thank you. Sounds interesting. :~) well do you know any resource or something i can dwell into
>>  for "Mersenne Twister (part of Python2.3),and "cryptographic random number generation" ??
>
>For Mersenne Twister, just search on Google.  Same for cryptographic
>random number generator (or cryptographic hash).  Mind you, the latter
>are HEFTY subjects, with lots of math.  The crypto RNG topics require a
>lot of knowledge about cryptography in general, to understand fully.
>
>>  And what u are saying is that everytime the seed([x]) where x = long int, it would return the same value??
>
>Yes.
>
>$ python2.3
>Python 2.3 (#1, Aug 12 2003, 13:06:21)
>>>> import random
>>>> help(random)
> 
>>>> random.seed(0)
>>>> random.random()
>0.84442185152504812
>>>> random.random()
>0.75795440294030247
>>>> random.random()
>0.420571580830845
>
>>>> random.seed(0)
>>>> random.random()
>0.84442185152504812
>>>> random.random()
>0.75795440294030247
>>>> random.random()
>0.420571580830845
>
>
>>  if it does thats then whats the point ??
>
>Setting the seed has several uses.  You can store its value to repeat
>sequences of events (sometime used in simulations).  You can create
>truely random seed values somehow, then use them to set the seed (the
>system time values are typically a small subset of all possible seeds,
>and similar starting seeds can produce simlar values on poorly made
>RNGs)
>
>>  Its better to use seed() which is based on the system's time then..
>
>If you don't care about the specific seed, yes, just let the system make
>one for you.  For cryptographic applications (which the RNGs we are
>talking about are NOT suited for, generally), it is very bad advice to
>use the system time, alone, as a seed.
>
>> And i think we can't use Mersenne Twister RNG in Python if i am not wrong.
>
>Python2.3 comes with it.  It is just an implementation detail (but it is
>generally considered a better, faster RNG than the previous
>implementation).  It is what I used above.
>
>Is there any reason you didn't send your reply to the Python mailing
>list?  I'm CC'ing the list, since there is nothing personal in this
>email, and it started on the list.
>
>
>-- 
>Chad Netzer
>
>

Yup!sorry. it was a mistake.. :~(.. Thank you anyway. I got your message clean & cut.
Cheers,
Ryan  

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