PHP7 - All instances of mt_rand() should be changed to random_int(); about probability-distributions-for-php HOT 3 CLOSED

I would be happy to promote the usage of the new random_ methods once they are inside our expected support window. I intend to deprecate the 5.x series soon for this project, but I don't want to remove backwards compatibility solely for the sake of breaking things.

Importantly, however, this is not a cryptographic library. That said, the cryptographic tests of randomness might have some interesting value in terms of what we mean by, say, "drawing from a uniform distribution." If there were a case to be made for this today, I would be willing to put a function_exists or userland polyfill style implementation in place.

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Exactly - while definitely not a cryptographic library, it would seem that the 'true' randomness of a distribution is important when being used for A/B testing or optimizations. If PHP documentation is correct, random_int() "should" produce a more truly reliable, mathematically correct result.

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This fundamentally comes down to what it means to be "truly" random. A question I've struggled with for a long time and is probably outside the scope of this chat. There are, however, a number of tests used to define true randomness.

I believe we should meet all the tests that would matter for that use case using Mersenne Twister, but it would be worth eventually adding unit tests to this library that ensure that is the case, to the extent they are meaningful.

For example, the Diehard tests or TestU01. I am not particularly familiar with the cryptographic randomness test suites, but the non-cryptographic properties should be sufficient with respect to A/B testing or any of the other common applications of these distributions like memoryless cache expiration or Monte Carlo simulations. Cryptographic tests aim to understand the impact of a form of randomness in a world where there is an active adversary.

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