Integrated crypto

Rogelio Serrano rogelio at
Thu Apr 8 17:31:00 PDT 2004

What about the clock skew between the processor clock and the 
PIT or whatever else kind of interval timer is used these days? 
The interval timer should be more stable that the processor 
clock. Im sure there is measurable entropy there.

On 2004-04-09 05:22:21 +0800 Adrian Fisher 
<mobiletiw at> wrote:

> It will only be slight variations (not accounting for weather) 
> but the temp 
> will change depending on the workload at the time for one.
> A
> Robert Connolly wrote:
>> On April 6, 2004 02:38 pm, Adrian Fisher wrote:
>>> Why not use CPU speed clocks?  I know they are known but 
>>> they very
>>> rarely match the quoted speed (this system is a P4 2.8 GHz 
>>> system and
>>> runs at different speeds regularly (sometimes faster, 
>>> sometimes slower)
>>> depending on the temperature of the room, what it is doing, 
>>> etc.
>>> Another option is to make use of the speed of cache and 
>>> memory, while
>>> these figures can be gained by the system they can be 
>>> incorporated into
>>> an algorythym that masks them.
>>> Just an idea.
>> How much do they vary? if it goes up or down by 1.00 degrees 
>> there would 
>> only be about 100 posibilities, if my math is right. It might 
>> help though; 
>> personaly I think hardware entropy should be sent to 
>> /dev/random. The 
>> frandom guy seems to have a good solution, but he says he's 
>> busy, might be 
>> a couple weeks before he can finish it. Another problem with 
>> using cpu temp 
>> is that it repeats.

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