Re: [TLS] RNG vs. PRNG

Nicolas Williams <Nicolas.Williams@oracle.com> Wed, 28 April 2010 02:23 UTC

Date: Tue, 27 Apr 2010 21:22:26 -0500
From: Nicolas Williams <Nicolas.Williams@oracle.com>
To: "Blumenthal, Uri - 0668 - MITLL" <uri@ll.mit.edu>
Message-ID: <20100428022226.GF10389@Sun.COM>
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Subject: Re: [TLS] RNG vs. PRNG
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On Tue, Apr 27, 2010 at 08:54:54PM -0400, Blumenthal, Uri - 0668 - MITLL wrote:
> From practical point of view an important difference between RNG and
> PRNG is that it is (in practice, realistically) impossible to
> compromise a "true" RNG - its random output is not reproducible, and
> there's no way to purposefully get the same sequence from it -

But there may be ways to attack the method by which the RNG works so as
to bias it.  Whereas there's no way to do that for a PRNG.  In general
it seems best to couple an RNG to a PRNG, using the former to seed and
periodically replenish the entropy pool of the latter, thus removing
biases from the RNG stream.

Nico
--

Re: [TLS] RNG vs. PRNG Blumenthal, Uri - 0668 - MITLL
Re: [TLS] RNG vs. PRNG Nicolas Williams
Re: [TLS] RNG vs. PRNG Marsh Ray
Re: [TLS] RNG vs. PRNG Steven Bellovin
Re: [TLS] RNG vs. PRNG Dean Anderson
Re: [TLS] RNG vs. PRNG Blumenthal, Uri - 0668 - MITLL
Re: [TLS] RNG vs. PRNG Nicolas Williams
Re: [TLS] RNG vs. PRNG Kemp, David P.
Re: [TLS] RNG vs. PRNG Marsh Ray
Re: [TLS] RNG vs. PRNG Nicolas Williams
Re: [TLS] RNG vs. PRNG Dean Anderson
Re: [TLS] RNG vs. PRNG Martin Rex