UUIDs (Universally Unique IDentifier), also known as GUIDs (Globally Unique IDentifier), according to RFC 4122, are identifiers designed to provide certain uniqueness guarantees.
- Invalid id format (UUIDs must be of the form “
xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx“, where x is one of [0-9, a-f] M is one of [1-5], and N is [8, 9, a, or b]
- Use of a low-quality source of randomness (such as
Thus, developers writing code for production environments are encouraged to use a rigorous, well-maintained implementation such as the uuid module.