
The Xorshift128+ random number generator fails BigCrush - adunk
https://lemire.me/blog/2017/09/08/the-xorshift128-random-number-generator-fails-bigcrush/
======
nkurz
The somewhat pointed and picky "tone" of Daniel's blog post might be clearer
if one looks at the comments from Vigna (the author of Xorshift128+) on one of
his other recent posts: [https://lemire.me/blog/2017/08/22/cracking-random-
number-gen...](https://lemire.me/blog/2017/08/22/cracking-random-number-
generators-xoroshiro128/)

Compare that to the exchange Daniel has with O'Neill (author of the competing
PCG random number generator) in another recent post:
[https://lemire.me/blog/2017/08/22/testing-non-
cryptographic-...](https://lemire.me/blog/2017/08/22/testing-non-
cryptographic-random-number-generators-my-results/)

~~~
LazyEvaluator
Can you explain what you mean?

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jlgaddis
Is this even a minor issue? I'm no expert but I don't think it is.

Xorshift128+ isn't -- and wasn't meant to be -- a CSPRNG. It's not like anyone
is gonna be using this in place of Yarrow or Fortuna, for example (or so we
hope!), or using it to generate important private keys (i.e., for GPG or TLS)
or anything like that.

~~~
Uzomidy
This has nothing to do with cryptographic security or predictability.

This is about whether the output of the PRNG passes statistical tests for
randomness. In a previous blog post by John D. Cook we saw that it failed the
PractRand statistical test suite [1], and now we see that it also fails the
older TestU01 suite, too.

When Xorshift128+ and Xoroshiro128+ were launched, they were claimed to be
statistically excellent. Those claims have been shown to be false.

[1] [https://www.johndcook.com/blog/2017/08/14/testing-rngs-
with-...](https://www.johndcook.com/blog/2017/08/14/testing-rngs-with-
practrand/)

------
tapirl
so this:
[https://github.com/golang/go/issues/21806](https://github.com/golang/go/issues/21806)
?

