OSSP uuid is an API for ISO C, ISO C++, Perl and PHP and a corresponding CLI for the generation of DCE 1.1,
ISO/IEC 11578:1996, and RFC4122 compliant Universally
Unique Identifiers (UUIDs). 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).
UUIDs are 128-bit numbers that are intended to
have a high likelihood of uniqueness over space
and time and are computationally difficult to
guess. They are globally unique identifiers that can be locally generated without contacting a
global registration authority.