OID entry name in OID container is not random

[Crypt32]

You have a function Get-RandomHex that generates random HEX for OID entry name in OID container. Actually, these OIDs are not truly random, their name depend on actual OID value and generated as follows:

OID entry name format: [X.Y]
Where X -- is first 16 (up to) characters of last OID arc. If last arc length exceeds 16 characters, it is stripped to 16 characters.
Where Y -- is MD5 hash calculated over unicode OID value string.

This technique is used in order to support O(1) OID lookup instead of enumerating all OID entries in OID container.

[GoateePFE]

Added notes from Twitter thread with Vadims here:
It is OID part (separated by dot). OID is hierarchical structure and each number have some meaning in a given context.
I'm not sure about public information on OID name generation, I got this from Vic Heller (Windows PKI team) six years ago.

[Crypt32]

excerpt from respective conversation.