Re: [PATCH v4 0/5] /dev/random - a new approach

From: Stephan Mueller <smueller@chronox.de>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: "David Jaša" <djasa@redhat.com>,
	"Andi Kleen" <andi@firstfloor.org>,
	sandyinchina@gmail.com,
	"Jason Cooper" <cryptography@lakedaemon.net>,
	"John Denker" <jsd@av8n.com>,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	"Joe Perches" <joe@perches.com>, "Pavel Machek" <pavel@ucw.cz>,
	"George Spelvin" <linux@horizon.com>,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 0/5] /dev/random - a new approach
Date: Sat, 18 Jun 2016 18:31:26 +0200	[thread overview]
Message-ID: <3381856.qSaz1KcX2Z@positron.chronox.de> (raw)
In-Reply-To: <20160618144408.GA5344@thunk.org>

Am Samstag, 18. Juni 2016, 10:44:08 schrieb Theodore Ts'o:

Hi Theodore,

> 
> At the end of the day, with these devices you really badly need a
> hardware RNG.  We can't generate randomness out of thin air.  The only
> thing you really can do requires user space help, which is to generate
> keys lazily, or as late as possible, so you can gather as much entropy
> as you can --- and to feed in measurements from the WiFi (RSSI
> measurements, MAC addresses seen, etc.)  This won't help much if you
> have an FBI van parked outside your house trying to carry out a
> TEMPEST attack, but hopefully it provides some protection against a
> remote attacker who isn't try to carry out an on-premises attack.

All my measurements on such small systems like MIPS or smaller/older ARMs do 
not seem to support that statement :-)

Ciao
Stephan