Re: How to make a random number
> On Wed, Apr 26, 2000 at 07:44:35PM -0500, Oleg Krivosheev wrote:
> > no idea who D&D are but the best way IMO
> > is to feed srand off /dev/urandom
> Depends on what you want. For most thing, secure randomness isn't
> nessecary, so the entropy buffers should be saved for when it is
> neccesary. /dev/urandom is also a Linux phonemon, and kills portability
> if used indiscrimitiely.
Portability issues aside...
Reading one number off of /dev/urandom does not drain the entropy pool
that much, but using it to seed srand() is kind of overkill.
srand/rand are not all that random to begin with.
I would suggest:
If you just want a few random numbers, and do not care how good they
are, go with srand(3)/rand(3).
If you want higher quality random numbers, but you do not need truely
random, entropy-laden numbers (most people do not need truly random
numbers), go with srandom(3)/random(3).
If you need truly random numbers for cryptographic work, then consider
/dev/urandom or /dev/random.
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