What's the key to the field "this certificate is encoded for the following purpose(s)" in ssl certificates ?

Question

In the property page of an SSL certificate (accessible in windows using mmc/certificates), each certificate is associated with a set of intended purposes looking either like this :

Protects e-mail messages

Proves your identity to a remote computer

Ensures the identity of a remote computer

Ensures software came from software publisher

Protects software from alteration after publication

All issuance policies

Or like this :

1.3.6.1.4.1.6449.1.2.1.3.4

How can I get the correspondance between those strings and a human-readable format ?

Answer 1

Those numbers are Object Identifier strings (aka OID)

There are several public repositories for OIDs (example)

For this string :

1.3.6.1.4.1.6449.1.2.1.3.4

the first part of the OID refers to Comodo, but the last part of the identifier is not available. It seems the only solution in this case is to ask Comodo directly.

Answer 2

This Link may help. Extended Key Usage