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

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-06-04 13:43:41

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).