: ( still don't know how to build ossp-uuid on windows with MSVC. Saito san's patch doesn't fix all errors during compiling...
I will try to combine this patch and the win32build on sf.net Same questions again: How was the dll file in the community binary built? How to avoid duplicate UUIDs then? thanks a lot. 2013-11-05 2:49 GMT+08:00 Christopher Browne <cbbro...@gmail.com>: > On Thu, Oct 31, 2013 at 3:42 PM, Robert Haas <robertmh...@gmail.com> > wrote: > > On Thu, Oct 31, 2013 at 2:44 PM, Garick Hamlin <gham...@isc.upenn.edu> > wrote: > >> I think using /dev/urandom directly would be surprising. At least it > would > >> have probably have taken me a while to figure out what was depleting the > >> entropy pool here. > > > > Perhaps so; a bigger problem IMHO is that it's not portable. I think > > the only way to solve this problem is to import (or have an option to > > link with) a strong, sophisticated PRNG with much larger internal > > state than pg_lrand48, which uses precisely 48 bits of internal state. > > For this kind of thing, I'm fairly sure that we need something with > > at least 128 bits of internal state (as wide as the random value we > > want to generate) and I suspect it might be advantageous to have > > something a whole lot wider, maybe a few kB. > > I mentioned the notion of building an entropy pool, into which one might > add various sorts of random inputs, under separate cover... > > The last time I had need of a rather non-repeating RNG, I went with > a Fibonacci-based one, namely Mersenne Twister... > > <http://en.wikipedia.org/wiki/Mersenne_twister> > > The sample has 624 integers (presumably that means 624x32 bits) as > its internal state. Apparently not terribly suitable for cryptographic > purposes, > but definitely highly non-repetitive, which is what we're notably > worried about for UUIDs. > -- > When confronted by a difficult problem, solve it by reducing it to the > question, "How would the Lone Ranger handle this?" > -- GaoZengqi pgf...@gmail.com zengqi...@gmail.com
