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.

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.