Re: $RANDOM not Cryptographically secure pseudorandom number generator

[Chet Ramey]

On 1/5/19 3:12 PM, Eduardo A. Bustamante López wrote:
> On Fri, Dec 28, 2018 at 10:24:50AM +0100, Ole Tange wrote:
> (...)
>> Patch attached.
>>
>> It is basically a copy of the code snippet from Wikipedia with a few
>> trivial wrappers.
>>
>> Apart from using Salsa20 the biggest change is that you can now seed
>> RANDOM with a string.
> 
> Nice!
> 
> I applied the Salsa20 RNG patch (slightly modified due to the recent changes 
> in
> variables.c, attached [1]) to the tip of `devel`
> (89b3a79dd4643f210f8443856214d558572733a5) and ran a couple of tests, to 
> answer
> the following questions:
> 
> - Does the new RNG generate uniformly distributed numbers? (Yes)
> - What is the performance impact (roughly 2X slower)
> - Does it break any existing tests? (Yes, easy to fix)

What's the period of the resulting RNG? That's the chief complaint with
the existing implementation.


-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/