Date: Sun, 6 Oct 2002 17:27:08 -0400 (EDT) From: Peter Leftwich <Hostmaster@Video2Video.Com> To: FreeBSD LIST <FreeBSD-Questions@FreeBSD.Org> Subject: Re: /dev/urandom is randomly cool Message-ID: <20021006172402.M71117-100000@earl-grey.cloud9.net> In-Reply-To: <20021006161444.H90352-100000@cactus.fi.uba.ar>
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On Sun, 6 Oct 2002, Fernando Gleiser wrote: > On Sun, 6 Oct 2002, Mikko Ty=F6l=E4j=E4rvi wrote: > > tr -cd a-zA-Z0-9 < /dev/urandom | dd bs=3D$len count=3D1 2>/dev/null It didn't work. My shell is tcsh so I tried: tr -cd a-zA-Z0-9 < /dev/urandom | dd bs=3D8 count=3D1 >& /dev/null And all I got was the next prompt. > > Which will give you $len random bytes from the set a-zA-Z0-9 (it reads > > a lot more from /dev/urandom than it produces though). > yes, and that is bad :( > It is not good to mess with /dev/[u]random more than what's really needed= , > because you can exhaust the entropy pool, and that's a Bad Thing. How large (deep?) is this entropy pool? > In your home box, for learning purposes, that's OK, but in a production b= ox > which needs a good working prng (for crypto session keys, auth cookies an= d the > like) it is not acceptable to "eat" all the entropy pool unless you have > a very good reason to do so. > =09=09=09Fer They ought to build motherboards with tiny lava lamps for randomness :) > > Another answer is, as always, "use perl" :-) > > $.02, > > /Mikko Yeah yeah-yeah. It's just nice having an all-inclusive OS, that's all! -- Peter Leftwich President & Founder Video2Video Services Box 13692, La Jolla, CA, 92039 USA +1-413-403-9555 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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