From: duwe@suse.de (Torsten Duwe)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 0/3] add support of hardware random generator on MediaTek MT7622
Date: Tue, 20 Jun 2017 16:59:33 +0200 [thread overview]
Message-ID: <20170620145933.GA4177@suse.de> (raw)
In-Reply-To: <1497968477.27946.5.camel@mtkswgap22>
On Tue, Jun 20, 2017 at 10:21:17PM +0800, Sean Wang wrote:
> Hi Herbert,
>
> thanks for effort reviewing on those patches.
>
> By the way, also loop in Torsten
>
> Could you kindly guide me how to determine appropriate
> rng->ops.quality value used by the driver?
>
> I have tested with rngtest on mtk-cir and the result is got as
> the below log shown. If the rngtest always gives the result for
> success rate over 99.8%, can I set the rng->ops.quality 998?
>
> rngtest: starting FIPS tests...
> rngtest: bits received from input: 20000032
> rngtest: FIPS 140-2 successes: 998
> rngtest: FIPS 140-2 failures: 2
No! You'd have to determine the failure threshold of the test and
apply some math to find a lower boundary of your RNG's entropy.
What the quality is for: your RNG produces bits, but not all of them
are completely independent of each other i.e. not completely random.
So you simply lower the quality rating to express the net entropy
contained in the data stream.
Torsten
next prev parent reply other threads:[~2017-06-20 14:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-12 15:56 [PATCH v2 0/3] add support of hardware random generator on MediaTek MT7622 sean.wang at mediatek.com
2017-06-12 15:56 ` [PATCH v2 1/3] dt-bindings: rng: add MediaTek MT7622 Hardware Random Generator bindings sean.wang at mediatek.com
2017-06-13 9:39 ` Matthias Brugger
2017-06-18 14:04 ` Rob Herring
2017-06-12 15:56 ` [PATCH v2 2/3] hwrng: mtk - add runtime PM support sean.wang at mediatek.com
2017-06-12 15:56 ` [PATCH v2 3/3] MAINTAINERS: add entry for MediaTek Random Number Generator sean.wang at mediatek.com
2017-06-20 3:40 ` [PATCH v2 0/3] add support of hardware random generator on MediaTek MT7622 Herbert Xu
2017-06-20 14:21 ` Sean Wang
2017-06-20 14:59 ` Torsten Duwe [this message]
2017-06-20 16:08 ` Sean Wang
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