[147918] in cryptography@c2.net mail archive
Re: [Cryptography] [RNG] /dev/random initialisation
daemon@ATHENA.MIT.EDU (Jerry Leichter)
Thu Oct 31 13:26:02 2013
X-Original-To: cryptography@metzdowd.com
From: Jerry Leichter <leichter@lrw.com>
In-Reply-To: <20131031004654.GB22665@savin>
Date: Thu, 31 Oct 2013 06:49:16 -0400
To: Peter Todd <pete@petertodd.org>
Cc: cryptography@metzdowd.com, jamesd@echeque.com
Errors-To: cryptography-bounces+crypto.discuss=bloom-picayune.mit.edu@metzdowd.com
On Oct 30, 2013, at 8:46 PM, Peter Todd wrote:
>> So: For extra sources to always be harmless, it must be the case that the bits are unpredictable *even if no new entropy arrives*. All that matters, in effect, is that the internal state be unknown and unpredictable *once*. BBS has this property, as (on different assumptions) do crypto-based PRNG's like Yarrow. But this has a performance cost, and I'm not sure that a Linux-style generator does. If you have it ... why would you need to allow additional (allegedly random) sources?
>
> This is why the Linux RNG allows anyone to add data to the pool as an
> unprivileged operation, but requires root to change the estimates of how
> much entropy is in the pool.
Ah, so like FIPS, Linux only accepts "real" entropy from "authenticated" sources. :-)
-- Jerry
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