You can export a PEM-format certificate from a Mac.

Become familiar with how to use Keychain Access on a Mac. For more information, see the Apple Support Web site at http://support.apple.com.

1

On the Mac, open Keychain Access.

2

From the sidebar, select System Roots.

3

Locate the certificate to export.

4

Select File > Export Items.

5

Select a location to save the certificate and select the Privacy Enhanced Mail (.pem) file format.