Identify Certificate Authority from public key
In OS X you can inspect all the system root certificates by doing the following:


Press cmd + spacebar and then type "keychain access" followed by return.
Select "System Roots" and "Certificates" in the left side pane.


You should now see all the root certs installed and used by OS X e.g.



You should be able to compare this list to the list of certs installed on your Ubuntu box.

PS: You can parse the cert.pem certificate via openssl x509 -text -noout &lt; /usr/local/etc/openssl/cert.pem. This won't give you a list of roots though, just a single cert (whose purpose I am unsure of).