[ath9k-devel] [PATCH v2] RANDOM: ATH9K RNG delivers zero bits of entropy

Hi Jason, Stephan,

Agree with Jason's point, also  understand Stephan's concern.  The date rate can be roughly estimated by 'cat /dev/random |rngtest -c 1000',  the average speed is 1111.294Kibits/s. I will sent the patch to disable ath9k RNG by default. 

Thanks,
Miaoqing

-----Original Message-----
From: Jason Cooper [mailto:jason at lakedaemon.net] 
Sent: Tuesday, August 09, 2016 1:30 AM
To: Stephan Mueller <[email protected]>
Cc: Pan, Miaoqing <[email protected]>; Ted Tso <[email protected]>; Sepehrdad, Pouyan <[email protected]>; herbert at gondor.apana.org.au; linux-kernel at vger.kernel.org; linux-crypto at vger.kernel.org; ath9k-devel <[email protected]>; linux-wireless at vger.kernel.org; ath9k-devel at lists.ath9k.org; Kalle Valo <[email protected]>
Subject: Re: [PATCH v2] RANDOM: ATH9K RNG delivers zero bits of entropy

Hi Stephan, Miaoqing Pan,

On Mon, Aug 08, 2016 at 08:41:36AM +0200, Stephan Mueller wrote:
> Am Montag, 8. August 2016, 02:03:36 CEST schrieb Pan, Miaoqing:
> > The entropy was evaluated by crypto expert,  the analysis report 
> > show the ADC with at least 10bits and up to 22 bits of min-entropy 
> > for a 32 bits value, we conservatively assume the min-entropy is 10 
> > bits out of 32 bits, so that's why set entropy quality  to  320/1024 = 10/32.

Ok, so the relevant commit is:

  ed14dc0af7cce ath9k: feeding entropy in kernel from ADC capture

Which refers to a previous commit:

  6301566e0b2d ath9k: export HW random number generator

> > Also we have explained in the commit message why can't use the HW 
> > RNG framework.