From: Mok-Kong Shen <mok-kong.shen@stud.uni-muenchen.de>
Date: Mon, 26 Oct 1998 17:21:08 +0800
To: David Honig <honig@sprynet.com>
Subject: Re: PRNGs and testers.
In-Reply-To: <19981021151835.A26267@krdl.org.sg>
Message-ID: <36343727.F2E8A921@stud.uni-muenchen.de>
MIME-Version: 1.0
Content-Type: text/plain



David Honig wrote:
> 

> An experiment
> 
> Run a block cipher in a feedback mode, generating a large data file.
> Any good cipher will pass Diehard's tests for structure.  So will
> a true random file.
> 
> (I've posted directions for producing decent true randomness from
> a detuned FM radio, soundcard, and 8->1 parity-reduction filtering.)
> 
> Now run Maurer's test; I've posted a version for blocksize = 16.
> The cipher-PRNG output will not have the entropy expected for randomness.
> The physical-random file will.
>

I don't see you have answered my question of whether a test has to
take into consideration how a sequence of numbers has been obtained.
Also what you wrote above seems to be less than clear. Do you suggest
that Mauerer's test is extremely good in deciding whether a sequence 
is TRULY random? (I think Maurer's test is good for investigating 
PRNG squences but maybe not used as a criterion between pseudo-
randomness and true randomness (whatever that may be defined)). 
What if some PRNGs pass Maurer's test?

M. K. Shen