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Combining 3 sources A,B and C is not obvious. The right thing to do is not A+B+C. It is A*B+C within a field (E.G. a GF(2^8) field, which maps to bytes). This is based on a 2006 paper by Barack Impagliazzo and Wigdersen (http://dl.acm.org/citation.cfm?id=1328011) that shows that this is a good extractor. You still need to post extract the output with an ...


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The Von Neumann whitener would not meet your needs, nor would the more modern Yuval Peres whitener (which is an iterated Von Neumann algorithm). This is because the input requirements for the algorithm are that the bits be statistically independent. No raw noise source provides statistically independent bits. Your only choice is to use an extractor that is ...


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Adding the source and length actually collects more entropy. Consider the case of using system counters as entropy sources. If at some timestamp CounterX=123, and CounterY=123, we actually retain at least one bit more entropy by stirring in a source identifier ("CounterX=123CounterY=123") instead of simply "123123". The source of the value is additional ...


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You can't contaminate the pool with low entropy data. Hash functions "extract" up to the output size or the hash - slightly less, because of collisions. The source number makes the output different for different sorces even if the input is the same. The length is needed because else we could not differate two small inputs from one large input with special ...


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Sometimes, rather than do cool math, the easiest approach is brute force! #include <stdio.h> #include <assert.h> int main() { enum { X0 = 3158, X1 = 1888, X2 = 1285, X3 = 1744, X4 = 253, X5 = 722, M_START = 3159 }; for (int m = M_START; m < 10*M_START; ++m) { for (int a = 2; a < m; ++a) { int c = X2 ...


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The goal of an ideal cryptographically secure pseudo-random number generator (CSPRNG) is to produce a stream of numbers that no machine can distinguish from a truly random stream of numbers. Formally, it's impossible to give a proof that a CSPRNG is truly random. That being said, there exists a family of statistical tests that can measure whether a sequence ...



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