[104653] in Cypherpunks
Re: PRNGs and testers.
daemon@ATHENA.MIT.EDU (Mok-Kong Shen)
Mon Oct 26 04:07:11 1998
Date: Mon, 26 Oct 1998 09:47:35 +0100
From: Mok-Kong Shen <mok-kong.shen@stud.uni-muenchen.de>
To: David Honig <honig@sprynet.com>
CC: cypherpunks@toad.com
Reply-To: Mok-Kong Shen <mok-kong.shen@stud.uni-muenchen.de>
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
