Re: [boost] [uuid] uuid::create() function

From: Andy (atompkins_at_[hidden])
Date: 2007-06-04 16:32:35

"Peter Dimov" <pdimov_at_[hidden]> wrote in
news:013b01c7a6cf$feb64e30$6407a80a_at_pdimov2: 

> Andy wrote:
> 
>> 4.  Use the current seed as the random numbers directly.  Will this
>> solution provide 'good' uuids?  That is, is this source of random
>> numbers good enough?
> 
> You'll need to perform statistical tests to be sure, but:
> 
> 1. On POSIX systems where /dev/urandom is available, it should be
> close to the best, at least in theory;
> 
> 2. Under a typical use case where the application only generates one
> UUID, it should be as good as any other RNG seeded with its entire
> state, and should be better than a RNG seeded with a 32 bit seed;
> 
> 3. In the multiple UUIDs case, I expect it to be competitive with any
> RNG, even though it only keeps 160 bits of state (another 160 bits -
> the old value of 'rd' - can also contribute, depending on the compiler
> and the use pattern). 
> 

Thanks!  This is the assurance I needed.

Andy.