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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:20:14 ADT
William H. Geiger III (whgiii@invweb.net)
Thu, 09 Jul 1998 05:11:50 -0500
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In <19980709095859.19285.qmail@anon.efga.org>, on 07/09/98
at 09:58 AM, Cicero <cicero@redneck.efga.org> said:
>Perry Metzger wrote:
>>"William H. Geiger III" writes:
>>> I would have to see the math and some test data before I would feel
>>> comfortable with this. There seems to be a big difference between using
>>> the time between to hit to generate X bits and taking the 2 deltas between
>>> 3 hits and then generating one bit of data from that.
>>
>>My big question is this: are there tools for taking a set of random
>>numbers dispersed according to a non-uniform distribution, like a
>>poisson or normal distribution, and turning them into a set of random
>>numbers over a uniform distribution? Given such tools, timing
>>intervals between the geiger counter ticks is probably safe --
>>otherwise, it may skew the results subtly.
>What do you see as the problems with:
> 1. Hash the data
> 2. Encrypt the data in CBC mode with the hash as key
>If the hash and cipher are both strong, this should be good.
>Is the concern over the entropy bottleneck caused the the small, fixed
>output of the hash?
>If so, then it would seem that one should:
> 1. Use the data as seed to a PRNG (pseudo random number generator)
> 2. Use the PRNG output (or xor it with the data, if you wish)
>If the PRNG were strong and had variably sized input, this should be
>good.
>This procedure seems particularly well suited to producing the desired
>output from the Geiger counter input. Among other things, it avoids the
>need to "adjust" the data, a process fraught with peril.
>Is the problem that you are not happy with the state of the art in PRNGs?
>The plethora of constructions that abound in the current body of
>standards might well inspire that response.
I think that the whole point of going with a RNG is due to the
inadequacies of software based systems. Using a RNG to seed a PRNG and you
are still limited to the strength of the PRNG though better than using a
PRNG without a RNG seed.
- --
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William H. Geiger III http://users.invweb.net/~whgiii
Geiger Consulting Cooking With Warp 4.0
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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:20:14 ADT