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Date:      Thu, 18 Sep 2003 19:36:36 -0600
From:      "David G. Andersen" <danderse@cs.utah.edu>
To:        "Devon H. O'Dell" <dodell@sitetronics.com>
Cc:        freebsd-security@freebsd.org
Subject:   Re: [Fwd: Re: FreeBSD Security Advisory FreeBSD-SA-03:12.openssh]
Message-ID:  <20030918193636.A94860@cs.utah.edu>
In-Reply-To: <3F6A5BBF.3020102@sitetronics.com>; from dodell@sitetronics.com on Fri, Sep 19, 2003 at 03:28:31AM %2B0200
References:  <3F6A5BBF.3020102@sitetronics.com>

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Devon H. O'Dell just mooed:
>
> If I'm not mistaken, /dev/random is a pseudo-random generator, which 
> means it has a certain period before it begins to repeat numbers (along 
> with that it just isn't truly random). So, please correct me if I'm 
> wrong, but doesn't this mean that when reading from /dev/random, you're 
> 'losing' randomness/entropy/whatever you're calling it?

   You're mistaken.  /dev/random stops feeding you random bits
when it doesn't have enough.  /dev/urandom depletes the entropy
pool, but when it starts to run out, it falls back to hashing
to generate pseudo-random sequences from the random bits that
it can obtain.

  -Dave

-- 
work: dga@lcs.mit.edu                          me:  dga@pobox.com
      MIT Laboratory for Computer Science           http://www.angio.net/
      I do not accept unsolicited commercial email.  Do not spam me.



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