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From Alex Herbert <>
Subject [rng] BigCrush results
Date Mon, 07 Oct 2019 13:43:49 GMT
I have found a bug in the stress test application that affects all the 
BigCrush results.

This was found when updating the stress test application to support 
64-bit testing within PractRand, and testing of upper and lower 32-bits 
from 64-bit out. An initial attempt to show that the lower 32-bits, bit 
reversed, of the XOR_SHIFT_1024_S systematically fail Linear Complexity 
tests did not work.

The bug was a dual reversal of the platform byte-order. Code was added 
to reverse the byte order in the link c application that read from stdin 
and passes numbers to BigCrush. Later code was added to reverse the byte 
order in the Java application so allowing Dieharder to work. The 
original c application should have been updated but was not (despite the 
fact I thought I had done this). So the byte order was not correct after 
a dual reversal and the BigCrush results refer to a byte reversed output 

I fixed the code and have verified that the stress test application can 
identify Linear Complexity failures in XOR_SHIFT_1024_S.

I am rerunning BigCrush for the other generators.

Testing of generators with PractRand is still under trial and will 
probably not make it for the 1.3 release. The only outstanding item for 
1.3 is continued work on updating the user guide.


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