Red Hat CERTIFICATE SYSTEM 7.1 - ADMINISTRATOR Administrator's Manual page 752

Registration of Object Identifiers
custom extension that points to a certificate practice statement (CPS) of your company. To
implement this, you need to compose the policy statement you want to include in the
extension, define an OID for the policy statement, and configure Certificate System with
the OID so that it can add that to the certificate it issues.
The use of an OID registered to another organization or the failure to register an OID may
carry legal consequences, depending on context. Registration may be subject to fees. For
more information, you should contact the appropriate registration authority.
To define or assign OIDs for your objects, you must know your company's arc, which is an
OID for a private enterprise. If your company doesn't have an arc, it needs to get one. This
URL contains information on registering for a company arc:
http://www.isi.edu/cgi-bin/iana/enterprise.pl
To understand why you need to have a company arc, check the information at this site:
http://www.alvestrand.no/objectid/2.16.840.1.113730.1.13.html
The site contains information on Red Hat-defined OID for an extension named Netscape
Certificate Comment. Note that the OID assigned to this extension is hierarchical and it
includes the Red Hat company arc, which is
owns has this prefix.
When determining whether to add custom extension to certificates, keep in mind that if the
extension exists in a certificate and if it is marked critical, the application validating the
certificate must be able to interpret the extension (including the optional qualifiers, if any),
or else it must reject the certificate. Since it's unlikely that all applications will be able to
interpret your company's extensions (embedded in the form of OIDs), the PKIX standard
recommends that the extension be always marked noncritical. For general guidelines on
setting extensions in certificates, see Appendix G, "Certificate and CRL Extensions."
752 Red Hat Certificate System Administrator's Guide • September 2005
. Every OID Red Hat
2.16.840.1.113730