[136039] in cryptography@c2.net mail archive
Re: combining entropy
daemon@ATHENA.MIT.EDU (Jonathan Katz)
Fri Oct 24 09:28:37 2008
Date: Fri, 24 Oct 2008 08:51:41 -0400 (EDT)
From: Jonathan Katz <jkatz@cs.umd.edu>
To: IanG <iang@systemics.com>
cc: Cryptography <cryptography@metzdowd.com>
In-Reply-To: <48E0C673.6040005@systemics.com>
[Moderator's note: top posting is not tasteful. --Perry]
I think it depends on what you mean by "N pools of entropy".
Are you assuming that one of these is sources is (pseudo)random, but you
don't know which one? Are you assuming independence of these difference
sources? If both these assumptions hold, then XOR will do the trick.
If your only assumption is that one of the sources has high min-entropy
(but may not necessarily be uniform), or if the independence assumption
does not hold, then you may need to use some form of randomness
extraction.
On Mon, 29 Sep 2008, IanG wrote:
> If I have N pools of entropy (all same size X) and I pool them
> together with XOR, is that as good as it gets?
>
> My assumptions are:
>
> * I trust no single source of Random Numbers.
> * I trust at least one source of all the sources.
> * no particular difficulty with lossy combination.
>
> iang
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