UUID

A UUID (universally unique identifier) is an arbitrary 128-bit identifier, and a standard set of guidelines for generating such an identifier. The goal is that each identifier will (with overwhelming probability) be unique, without need of a central authority.

Some of the bits in a UUID are not random, and are used to indicate the UUID version number, etc.

The standard way to display a UUID is to use hex encoding, with four hyphens added at particular positions. It typically looks something like this: 00000000-1111-2222-3333-444444444444

See also GUID, the Microsoft version of UUID.

Any UUID (or GUID) can be converted into a URI by inserting "urn:uuid:" at the beginning, and then followed by the standard form, with letters in lowercase. This allows a UUID to be represented anywhere a URI is allowed, such as the identification of a node in a RDF graph.

A UUID can also be convert into a OID, by prefixing "2.25." followed by the decimal representation of the 128-bit number of the UUID (as a single number, not broken up into parts).

Links

 * RFC 4122
 * New UUID Formats (internet draft)
 * Universally unique identifier