Re: Re: PRNG: Raise warning and/or provide better pseudo random generator?
| From: | Yasuo Ohgaki | Date: | Wed, 24 Feb 2016 22:09:45 +0000 |
| Subject: | Re: Re: PRNG: Raise warning and/or provide better pseudo random generator? | ||
| References: | 1 2 3 4 5 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-91383@lists.php.net to get a copy of this message | ||
Hi all,
On Thu, Feb 25, 2016 at 6:31 AM, Yasuo Ohgaki <yohgaki@ohgaki.net> wrote:
>> I think it would be preferable to wait a bit -- there's clearly interest in
>> replacing rand/mt_rand etc with a higher quality PRNG, so maybe lets give
>> people time to create a proposal for that before we start throwing warnings.
>
> Reasonable suggestion!
> Adding warnings is trivial. It could done before RC.
> I'll wait until then.
I updated the doc for the time being.
http://svn.php.net/viewvc?view=revision&revision=338662
MT rand range is 2^32, but our mt_rand() implementation is 2^31.
http://lxr.php.net/xref/PHP_5_6/ext/standard/rand.c#331
Because RAND_RANGE() macro simply does arithmetic on supplied
parameters, out of range values result in biased numbers. Therefore, I
replaced mt_rand() caution to my warning.
Regards,
--
Yasuo Ohgaki
yohgaki@ohgaki.net