# Tag Info

1

Depending on the parameters of the Gaussian, every $X_i$ byte will have some entropy < 8 bits. So you cannot produce cryptographically random bytes from each of them, unless you add some entropy from another source. You can, however, turn them into smaller values. For example, if they have at least 1 bit of entropy, you can turn them into bits. Like if ...

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Just use a small block sized block cipher in counter mode and filter out elements that are out of range.

6

Yes, you can certainly do this, and there has been a lot of theoretical work in the area. At a high level, what this is called is a randomness extractor (Wikipedia): A randomness extractor, often simply called an "extractor", is a function, which being applied to output from a weakly random entropy source, together with a short, uniformly random seed, ...

2

First things first: a PRNG (Pseudo Random Number Generator) can not provide a one-time pad. As a reminder: a one-time pad… has to be truly random, must be at least as long as the plaintext, is never reused in whole or in part, and is kept completely secret. Only when all four points are met, we´re talking about OTP. Your PRNG idea fails to meet those ...

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Answered (I think pretty well) by this Reddit thread: All tests of RNGs are based on a "null hypothesis", meaning if they fail, they show the RNG may be flawed. But if they pass, it does not mean it is good. Therefore, the question should be re-worded as "what values constitute failing the ENT tests". Entropy: compressibility > 10% is probably a pretty ...

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Theoretically a TRNG provides more security, since its not deterministic and it cannot be predicted. But provided a PRNG is implemented correctly the repetition period is very large $>2^{256}$. Unless you have a cryptographic application that uses the full iteration length the PRNG is not the weakest spot in the cryptosystem. Taken PRNG like ...

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Entropy as defined in information theory and cryptography is a difficult concept. One of the most common fallacies is that a piece of data has or "contains" entropy by itself. People who misunderstand this talk about bit streams having entropy, or measuring entropy of a piece of data. Or measuring entropy of a RNG. To measure entropy you need a data source, ...

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I see no reason to expect your construction to be cryptographically secure. A single MWC generator is not something that was ever designed to be cryptographically secure. A cryptographically-strong PRNG needs to be designed in a very different way from a non-crypto PRNG. In particular, it sounds like MWC was designed to have a long period. But having a ...

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