[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

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.

> -- 
> David Starner - dstarner98@aasaa.ofe.org
> The hell that is supposedly out there could be no worse than
> the hell that is sometimes seen in here.
> -- 
> To UNSUBSCRIBE, email to debian-devel-request@lists.debian.org
> with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org

     Buddha Buck                             bmbuck@14850.com
"Just as the strength of the Internet is chaos, so the strength of our
liberty depends upon the chaos and cacophony of the unfettered speech
the First Amendment protects."  -- A.L.A. v. U.S. Dept. of Justice

Reply to: