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Re: [Bug]? -iR <num_hosts> on windows XP generates duplicate targets
From: doug () hcsw org
Date: Thu, 1 May 2008 22:25:53 -0700

On Fri, May 02, 2008 at 03:53:47AM +0000 or thereabouts, Brandon Enright wrote:
I did the same.  I was not able to run -iR 5000 even with hours of
waiting.  I love Linux but this really is the fault of the kernel
developers not recognizing the problem or accepting patches to
"fix" /dev/random.  Yarrow, Fortuna, and other RNG schemes have been
coded up but haven't been integrated.

No, IMO this is not a kernel problem. /dev/random (or /dev/srandom on
oBSD) MUST block if it doesn't have enough entropy in the pool. For
example, when you are creating a GPG key and it tells you to wave your
mouse around or whatever, it is doing this to ensure that you will
get a key that is not predictable, even if an attacker knows exactly
when your system was booted, all PIDs of processes on your system,
and even has a long sequence of random numbers generated by your system
earlier.

All PRNGs have to be seeded. /dev/random ensures that your seeds
really will be unpredictable and will never give you random data
that hasn't been gathered from the "real world". If you can't take
the blocking, well, that's what arandom/urandom are for.

Remember netscape in 95? They seeded their PRNG with the PID, the
PPID, and the time, all MD5ed, and it still wasn't good enough:

http://www.cs.berkeley.edu/~daw/papers/ddj-netscape.html

Doug

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