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Date: Mon, 18 Dec 2000 09:21:58 +0100
From: Karel Kulhavy <clock@atrey.karlin.mff.cuni.cz>
To: linux-kernel@vger.kernel.org
Subject: Re: /dev/random: really secure?
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> 	There are hidden sources of entropy. One is clock skew between the keyboard
> processor's clock, the keyboard controller's clock, and the CPU clock
> generator's PLL. Another is data motion between the CPU cache and main

In the RFC 1750, they write it is not recommended to rely on computer clocks to
generate random. Isn't it this case?

> > depends solely on the network packets. These can be manipulated and their
> > leading edge precisely sniffed. I think here exists a severe risk of
> > compromise. Am I right?
> 
> 	Nope. There is no way to sniff their leading edge accurate to a billionth
> of a second. If you have a 1Ghz Pentium 3, that's the accuracy you'd need.

But it reduces the entropy. When I have a 486/66 and sniff packets accurately to
3MHz, only 4 bits remain. These bits need not to show a uniform distribution so
it could be even easier to guess them.

Clock
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