Package rand contains additional math/rand/Source64 implementations for use with math/rand's Rand type. The standard math/rand Source64 pre v1.17 used an Additive Lagged Fibonacci Generator (ALFG) originally designed by DP Mitchell and JA Reeds for Bell Lab's Plan9 operating system. From 1.17 it uses the wyrand (runtime.fastrand) PRNG https://github.com/wangyi-fudan/wyhash SplitMix64 (period 2^64) XOshiro256 (xoshiro256** in the literature) (period 2^256 - 1) PCG (Permuted Congruential Generator) (period 2^128) Relative speeds (not very scientific) The statistical testing suite Big Crush/TU01 is described at http://simul.iro.umontreal.ca/testu01/tu01.html and available at https://github.com/umontreal-simul/TestU01-2009/