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SubjectRe: [PATCH] nvmem: sunxi-sid: SID content is not a valid source of randomness
On Tue, 25 Oct 2016 07:38:55 +0200
LABBE Corentin <clabbe.montjoie@gmail.com> wrote:

> > On Sat, Oct 22, 2016 at 03:53:28PM +0200, Corentin Labbe wrote:
> > > Since SID's content is constant over reboot,
> >
> > That's not true, at least not across all the Allwinner SoCs, and
> > especially not on the A10 and A20 that this driver supports.
> >
>
> On my cubieboard2 (A20)
> hexdump -C /sys/devices/platform/soc\@01c00000/1c23800.eeprom/sunxi-sid0/nvmem
> 00000000 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000100 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000200
> cubiedev ~ # reboot
> cubiedev ~ # hexdump -C /sys/devices/platform/soc\@01c00000/1c23800.eeprom/sunxi-sid0/nvmem
> 00000000 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000100 16 51 66 83 80 48 50 72 56 54 48 48 03 c2 75 72 |.Qf..HPrVTHH..ur|
> 00000110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
> *
> 00000200
>
> So clearly for me its constant.

Even after power off/power on?

--
Ken ar c'hentañ | ** Breizh ha Linux atav! **
Jef | http://moinejf.free.fr/

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