Why are UUID / GUID's in the format they are?
- by Xeoncross
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:
3F2504E0-4F89-11D3-9A0C-0305E82C3301
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:
uuid:xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
