RE: [PHP] GUID or any other unique IDs

On Tue, 2005-10-25 at 14:47 +0400, Denis Gerasimov wrote: > > $unique_id = sha1( uniqid( mt_rand(), true ) ); > > > > which should be very unique and suitable for most purposes. > > I really need millions of unique IDs - hashing is not suitable for this task > (I think so) :-(. Any more ideas? The above function could generate much more than millions of unique IDs. You have 1.46 x 10^48 possible hashes, and with an input of the current time in microseconds prefixed by a Mersenne Twister random number and suffixed by additional entropy from the combined linear congruential generator, collisions should be *very* improbable, even when generating IDs on multiple hosts all at the same time. -- Jasper Bryant-Greene General Manager Album Limited e: jasper@album.co.nz w: http://www.album.co.nz/ p: 0800 4 ALBUM (0800 425 286) or +64 21 232 3303 a: PO Box 579, Christchurch 8015, New Zealand