Re: [PATCH 2/2] ath9k: export HW random number generator

[Kalle Valo <kvalo-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

Stephan Mueller <smueller-T9tCv8IpfcWELgA04lAiVw@public.gmane.org> writes:

>>-rw-rw-r-- 1 lex lex 2564096 Jul 27 11:36 hwrng.out
>>-rw-rw-r-- 1 lex lex 2468394 Jul 27 11:36 hwrng.out.bz2
>>
>>Do i understand it correctly, in case of hwrng bzip was able to find
>>enough pattern to compressed the data? Even with format overhead?
>>
>>I'm no an expert, help of an expert would be welcome, added some more
>>people to CC
>
> This one does not look good for a claim that the RNG produces white noise. An 
> RNG that is wired up to /dev/hwrng should produce white noise. Either by 
> having an appropriate noise source or by conditioning the output of the noise 
> source.
>
> When conditioning the output, you have to be careful about the entropy claim. 
> For example, you cannot state that the data stream from your noise source has 
> close to one bit of entropy for each obtained bit. Thus, the conditioner must 
> ensure that the data from the noise source is collected and its entropy is 
> maintained and accumulated.
>
> However, the hwrandom framework does not provide any conditioning logic. And I 
> would say that such conditioner logic should not reside in a driver either. I 
> would say that the discussed RNG does not seem fit for hooking it up with the 
> hwrandom framework.

Based on the discussion I'm going to revert this patch, at least for
now.

-- 
Kalle Valo
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