• @FooBarrington
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    38 months ago

    I know what you’re trying to get at, but my point is this: Imagine you have two streams of data, one from a CSPRNG, and one from what you call “true randomness”. How can you tell which one is which (as long as you’re staying under the CSPRNGs limit from your initial entropy)?

    If you can’t tell me a way, there is no functional difference between these two options. So what advantage would true randomness hold?

    • @[email protected]
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      08 months ago

      I said this in another comment, but while I agree that there is virtually no functional difference, and in the vast majority of cases truly random and functionally random are equivalent, that doesn’t mean that something which is functionally random is truly random.

      • @FooBarrington
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        38 months ago

        But it is truly random for all intents and purposes, since the input is truly random. Just because the process contains deterministic steps doesn’t mean the input entropy isn’t true entropy anymore.

        • @[email protected]
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          08 months ago

          And a pool is clean for all intents and purposes. There is still a distinction though. The fact that it is deterministic inherently makes it less random than true randomness.

            • @[email protected]
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              08 months ago

              If you take the original values used to determine the final “random number” and run them through the same sequence of calculations, you will always reach the same value.

              We rely on the fact that the inputs are so numerous and/or difficult to replicate to deem the final value “random”. But that doesn’t mean that the value cannot be reached by a second party given perfect knowledge of the original state of all inputs.

              True randomness, on the other hand, is impossible to calculate even with that perfect knowledge, because we aren’t relying on the state of inputs running through a calculation.

              • @FooBarrington
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                8 months ago

                But that’s my point: just because you apply deterministic steps to a truly random input doesn’t make the output not truly random. You use real entropy as your starting point, which is literally exactly what you call “true randomness”. This means the output has the same level of “true randomness” as your “truly random” input, because you mathematically don’t lose entropy along the way.

                To put it more simply: you’re arguing from a philosophical perspective, not a mathematical one.

                • @[email protected]
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                  08 months ago

                  The input is not truly random though. If it was, we could just use that input, with no other steps, and have a truly random output. You’re confusing an unknown state with randomness.

                  • @FooBarrington
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                    28 months ago

                    No, it actually and literally is truly random. You’d need to know everything about the hardware itself and the environment around it in incredible detail (incl. the temperature of every individual small patch of material, air flow and the state of air in and around the case) to reliably predict the initial entropy for a given modern system, since tiny changes in e.g. temperature will completely change the input.

                    It’s only a small bit of entropy, but enough to kick-start the RNG in a way that can reliably create high-quality entropy.