How are GUIDs created?

[Steve8x8]

Anyone knows how WP codes (GCxxxxx) are converted to GUIDs (xxxxxxxx-
xxxx-xxxx-xxxx-xxxxxxxxxxxx), user names to GUIDs, log LIDs to LUIDs?
I've been trying md5sum but didn't succeed. Must be very close though.
Any suggestions?
Thanks, S.

[Steve8x8]

UUIDs (see Wikipedia article), at least the ones used by gc, are flagged as "random" (it's one of the hex digits, _not_ leaving enough space for md5sum's full length).
I have seen queries for WIDs fail (temporarily) - supposedly because the database didn't properly translate them into GUIDs, the caches were reported as non-existing.
Therefore my guess is: there isn't such a mapping, or at least it's not reproducible in terms of algorithms. WIDs (and LIDs) are assigned in lexicographic order (base-31), and the UUIDs *may* reflect the creation time, but I doubt they can be translated back.
Someone using automated logging (GSAK etc) may try to produce a sequence of logs (GL??????) and check the corresponding LUIDs...