Globally Unique Identifiers (GUID) are a grouped string with a specific format which I assume has a security reason.
A GUID is most commonly written in text as a sequence of hexadecimal digits separated into five groups, such as:
Why aren't GUID/UUID strings just random bytes encoded using hexadecimal of X length?
This text notation contains the following fields, separated by hyphens:
| Hex digits | Description |------------------------- | 8 | Data1 | 4 | Data2 | 4 | Data3 | 4 | Initial two bytes from Data4 | 12 | Remaining six bytes from Data4
There are also several versions of the UUID standards.
Version 4 UUIDs are generally internally stored as a raw array of 128 bits, and typically displayed in a format something like: