X509 uses Object Identifiers (OIDs) to uniquely identify things, for example one assigns a OID to their Certificate Policy Statements (CPS) so that it is possible to programmatically detect if a certificate meets a specific policy.
OIDs are managed as a namespace, this prevents “collision”. As such one needs to request an OID be assigned to them.
The “arc” part comes when you get your OID, you can assign any number you want at the end of your OID. For example, one might be assigned 18.104.22.168 and decide to “break” it up into chunks as follows:
- 22.214.171.124.2 – Documents
- 126.96.36.199.3 – Certificate Extensions
- 188.8.131.52.4 – Resource Identifiers
Underneath each of these you would assign unique numbers by appending a new number, for example 184.108.40.206.2.1 might be your CAs Certificate Practice Statement (CPS).
So how do you get one of these OIDs then? That’s easy it’s Internet Assigned Numbers Authority (IANA) who assigns these, they call them Private Enterprise Numbers. Getting one is easy enough just fill out a web application form. To do that you will only need 7 pieces of information, these include:
- Organization Name
- Organization Address
- Organization Phone
- Contact Name
- Contact Address
- Contact Phone
- Contact Email
Remember the idea is that the information you provide here will be used for people to reach you if they want to ask questions about these things you have uniquely identified so choose the values wisely.
It can take up to 60 days to get one of these (although usually the application is processed in about one week).
Once you got the object identifier, you should register the code on the site www.oid-info.com and/or www.alvestrand.no in this way will be easily accessible by those who are seeking information about the owner of object identifier.
Hope this helps.