UUID stands for Universally Unique Identifier, a standard for software construction and part of the Open Software Foundation's Distributed Computing Environment. A UUID is a 128-bit value that can be calculated by a certain algorithm. To improve efficiency, commonly used UUIDs can be shortened to 16 bits. UUIDs are used to identify attribute types and are considered unique identifiers across all space and time. In general, it can be guaranteed that any UUID generated anywhere is truly unique. One advantage of using UUIDs is that new identifiers can be created for new services. The standard UUID format is: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (8-4-4-4-12).