Re: Seeding random() randomly
Re: Seeding random() randomly
- Subject: Re: Seeding random() randomly
- From: Michael Hall <email@hidden>
- Date: Fri, 27 May 2011 05:12:11 -0500
On May 26, 2011, at 10:32 PM, Jens Alfke wrote:
>
> On May 26, 2011, at 7:15 PM, Kevin Bracey wrote:
>
>> srandom(time(NULL));
>
> It’s never a good idea to seed a RNG with something guessable like this. (An old exploit against the Netscape browser’s SSL implementation was made possible in part by doing exactly that.)
>
> All you have to do is call srandomdev() once; that will seed the generator used by random() with some extremely random (“high-entropy”) data read from /dev/random, which is generated by the kernel through all kinds of black magic.
It lacks 'good' confusion.
http://en.wikipedia.org/wiki/Confusion_and_diffusion
Sort of like the OP's seed multiply, which just led to 'bad' confusion.
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