[cryptography] Intel RNG

Marsh Ray marsh at extendedsubset.com
Tue Jun 19 16:54:37 EDT 2012

On 06/19/2012 02:11 PM, coderman wrote:
> the sanity checks, being on die, are limited. you can't run DIEHARD
> against this in a useful manner because the DRBG obscures anything
> useful.

I don't think there's anything useful diehard (specifically) is going to 
tell you.

The raw entropy source output would not be expected to pass diehard. The 
CR report shows visible artifacts in that FFT graph. The entropy 
estimation function one would apply to that source would likely be much 
simpler than the diehard suite. Just a sanity check that the output is 
actually changing once in a while would go a long way towards 
eliminating the most common failure modes.

On the other hand, the AES CTR DRBG output will always pass diehard, 
whether it contains any entropy or not.

- Marsh

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