hi, thanx a lot,there is one more doubt.

The rules of physics are those that don't change from time to time, or place to place

i tend to disagree with this. the hierarchy goes like okay let us say that two bodies with mass attract each other. it was an observation of a physical body,then we make a mathametical model of the phenomenon. Based on the mathametical model we make laws of physics. The mathametical observations rely on the parameters that are taken to make the mathametical model. if the parameters changes,the mathametical model will have to be changed and new laws have to be brought. with what certainy can we say that additional parameters will not be added or removed and that the laws of physics will stay true for ever? If a new parameter ever gets added may be two bodies with mass may repell each other. can we say that these parameters will never change? Regards Data. --- Optimizzin Al-gorithym <al@qaeda.org> wrote:

At 05:45 AM 7/14/02 -0700, gfgs pedo wrote:

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it is said that atmospheric noise is random but how can we say for sure.

Physics, chaos, the growth of initial uncertainty as systems evolve, energy/time required to make measurements to arbitrary precision.

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what if the parameters giverning atmospheric noise vary frm time 2 time.

The rules of physics are those that don't change from time to time, or place to place. Certainly the e.g., wind speed does.

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so can we say atmospheric noise is random or a coin flipping is random-only because it passes die hard test or other randomness tests-which is an indicator of randomness with the current defenition of parameters in determing randomness?

No, since 'anything through a whitener passes' these tests. The integers (0, 1, 2..) fed into DES will pass. (Equivalently) A low-entropy source fed into a hash will pass.

[Historical note: this is why Intel should make its raw RNG data available in chips with whitened-output RNG functions]

To have a true RNG, You *must* have a physical understanding of the source of entropy whence you distill the pure bits (whether or not you feed it into a whitener after distillation). Precisely because a 'black box' may be a deterministic (if you know the secret) PRNG. By 'distill' I mean reduce N bits to M, N > M, in such a way as to increase the entropy of the resultant M bits.

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is there truly random or that we can say with certain degre of confidence that they are nearly random as all current evidence poits so.

'Random' should be taken to mean 'ignorant of'. It suffices that we (and our adversary) are ignorant of the detailed conditions inside a noise diode, unstable atomic nucleus, atmospheric (or FM radio) noise receiver, etc. Philosophical discussions about 'true randomness' ("Is there a deeper/smaller level of description in which apparently-random events are based or emerge from?") are beyond the scope of this rant.

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