From: Clemens Ladisch <clemens@ladisch.de>
To: Stephan Mueller <smueller@chronox.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>, Pavel Machek <pavel@ucw.cz>,
sandy harris <sandyinchina@gmail.com>,
linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
Nicholas Mc Guire <der.herr@hofr.at>
Subject: Re: [PATCH] CPU Jitter RNG: inclusion into kernel crypto API and /dev/random
Date: Thu, 14 Nov 2013 19:30:22 +0100 [thread overview]
Message-ID: <528516BE.2040204@ladisch.de> (raw)
In-Reply-To: <3127174.i8ueAho43m@tauon>
Stephan Mueller wrote:
> Am Donnerstag, 14. November 2013, 11:51:03 schrieb Clemens Ladisch:
>> An attacker would not try to detect patterns; he would apply knowledge
>> of the internals.
>
> I do not buy that argument, because if an attacker can detect or deduce
> the internals of the CPU, he surely can detect the state of the
> input_pool or the other entropy pools behind /dev/random.
With "internals", I do not mean the actual state of the CPU, but the
behaviour of all the CPU's execution engines.
An Intel engineer might know how to affect the CPU so that the CPU
jitter code measures a deterministic pattern, but he will not know the
contents of my memory.
>> Statistical tests are useful only for detecting the absence of entropy,
>> not for the opposite.
>
> Again, I fully agree. But it is equally important to understand that
> entropy is relative.
In cryptography, we care about absolute entropy, i.e., _nobody_ must be
able to predict the RNG output, not even any CPU engineer.
Regards,
Clemens
next prev parent reply other threads:[~2013-11-14 18:31 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-11 18:38 [PATCH] CPU Jitter RNG: inclusion into kernel crypto API and /dev/random Stephan Mueller
2013-10-12 1:45 ` Sandy Harris
2013-10-12 3:28 ` Theodore Ts'o
2013-10-12 19:04 ` Stephan Mueller
2013-10-12 20:12 ` Stephan Mueller
[not found] ` <CACXcFm=_jmeKe2YYbHDi-jTGX-23hDsDeu_weWQkr2F_FpE_6g@mail.gmail.com>
2013-10-14 13:38 ` Fwd: " Sandy Harris
2013-10-14 14:12 ` Stephan Mueller
2013-10-14 14:26 ` Stephan Mueller
2013-10-14 14:14 ` Sandy Harris
2013-10-14 14:40 ` Stephan Mueller
2013-10-14 15:18 ` Sandy Harris
2013-10-14 15:26 ` Stephan Mueller
2013-10-14 15:46 ` Sandy Harris
2013-10-14 21:33 ` Sandy Harris
2013-10-15 6:23 ` Stephan Mueller
2013-10-28 15:40 ` Stephan Mueller
2013-10-28 16:06 ` Henrique de Moraes Holschuh
2013-10-28 16:15 ` Stephan Mueller
2013-10-28 21:45 ` Theodore Ts'o
2013-10-29 8:42 ` Stephan Mueller
2013-10-29 13:24 ` Theodore Ts'o
2013-10-29 14:00 ` Stephan Mueller
2013-10-29 22:25 ` Stephan Mueller
2013-11-02 11:01 ` Pavel Machek
2013-11-02 11:12 ` Pavel Machek
2013-11-03 7:20 ` Stephan Mueller
2013-11-03 12:41 ` Theodore Ts'o
2013-11-05 12:20 ` Stephan Mueller
2013-11-06 11:49 ` Stephan Mueller
2013-11-06 12:43 ` Theodore Ts'o
2013-11-06 12:51 ` Stephan Mueller
2013-11-06 13:04 ` Theodore Ts'o
2013-11-06 13:24 ` Pavel Machek
2013-11-07 0:36 ` Nicholas Mc Guire
2013-11-07 5:21 ` Stephan Mueller
2013-11-09 22:04 ` Clemens Ladisch
2013-11-10 1:10 ` Stephan Mueller
2013-11-10 16:31 ` Clemens Ladisch
2013-11-10 17:21 ` Stephan Mueller
2013-11-10 20:28 ` Clemens Ladisch
2013-11-13 3:12 ` Stephan Mueller
2013-11-13 11:51 ` Clemens Ladisch
2013-11-13 15:15 ` Stephan Mueller
2013-11-13 17:14 ` Pavel Machek
2013-11-14 10:51 ` Clemens Ladisch
2013-11-14 18:01 ` Stephan Mueller
2013-11-14 18:30 ` Clemens Ladisch [this message]
2013-11-14 18:34 ` Stephan Mueller
2013-11-11 2:58 ` H. Peter Anvin
2013-11-07 1:03 ` Nicholas Mc Guire
2013-11-07 5:26 ` Stephan Mueller
2013-11-09 22:04 ` Clemens Ladisch
2013-11-10 1:16 ` Stephan Mueller
2013-11-03 23:32 ` Pavel Machek
2013-11-05 12:25 ` Stephan Mueller
2013-11-05 13:45 ` Stephan Mueller
2013-11-06 11:42 ` Stephan Mueller
2013-11-06 13:26 ` Pavel Machek
2013-11-07 3:12 ` Stephan Mueller
2013-11-13 3:37 ` [PATCH] CPU Jitter RNG: Executing time variation tests on bare metal Stephan Mueller
2013-10-30 12:59 ` [PATCH] CPU Jitter RNG: inclusion into kernel crypto API and /dev/random Sandy Harris
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