UUIDs are 128 bit numbers which are intended to have a high likelihood
of uniqueness over space and time and are computationally difficult
to guess. They are globally unique identifiers which can be locally
generated without contacting a global registration authority. UUIDs
are intended as unique identifiers for both mass tagging objects
with an extremely short lifetime and to reliably identifying very
persistent objects across a network.

OSSP uuid is a ISO-C:1999 application programming interface (API)
and corresponding command line interface (CLI) for the generation
of DCE 1.1, ISO/IEC 11578:1996 and RFC 4122 compliant Universally
Unique Identifier (UUID). It supports DCE 1.1 variant UUIDs of version
1 (time and node based), version 3 (name based, MD5), version 4
(random number based) and version 5 (name based, SHA-1). Additional
API bindings are provided for the languages ISO-C++:1998, Perl:5 and
PHP:4/5. Optional backward compatibility exists for the ISO-C DCE-1.1
and Perl Data::UUID APIs.

Homepage:
http://www.ossp.org/pkg/lib/uuid/
