What is a UUID?
UUID (or GUID) is an acronym for 'Universally Unique
Identifier' (or 'Globally Unique Identifier'). The term GUID is
generally used by developers working with Microsoft technologies,
while UUID is used everywhere else.
128-bits is big enough and the generation algorithm is unique
enough that if 1,000,000,000 UUIDs per second were generated for
1 year the probability of a duplicate would be only 50%.
UUIDs are used in enterprise software development in C#, Java,
and C++ as database keys, component identifiers or just about
anywhere else a truly unique identifier is required.