The GUID / UUID should be at least 32 characters and should stay in the ASCII range to avoid trouble when passing them around.
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.