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Date:      Thu, 08 Jun 2000 19:24:10 +0200
From:      Mark Murray <mark@grondar.za>
To:        Kris Kennaway <kris@FreeBSD.ORG>
Cc:        Mark Murray <mark@grondar.za>, current@FreeBSD.ORG
Subject:   Re: mktemp() patch 
Message-ID:  <200006081724.TAA00705@grimreaper.grondar.za>
In-Reply-To: <Pine.BSF.4.21.0006072338550.73192-100000@freefall.freebsd.org> ; from Kris Kennaway <kris@FreeBSD.ORG>  "Wed, 07 Jun 2000 23:44:02 MST."
References:  <Pine.BSF.4.21.0006072338550.73192-100000@freefall.freebsd.org> 

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> > What is the purpose of this? It looks hugely wasteful to me. If you
> > really need a single random bit, it is not good to waste a block of
> > hard-gained gryptographic randomness; can you not use a pseudo-random
> > bit-generator?
> 
> arc4random() does not consume entropy except the first time it is called
> and when explicitly reseeded through arc4random_stir(). Apart from that
> it's a deterministic function (the arc4 stream cipher), but it's still a
> reasonably good cryptographic PRNG because arc4 is a cryptographically
> strong algorithm.

But I repeat myself; are you still intending to use cryptographic security
for one bit? What does that buy you? An attacker will laugh at the waste
of resources that went into a coin-flip :-). Much better is to use something
cheaper like time-of-day XOR 1 << whatever.

M
--
Mark Murray
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