When generating certificates for use with iOS, be it push notifications or Passbook, it’s sometimes necessary to take these certificates and export them, so they can be used on a Windows machine. If you want to generate the certificates using only Windows, please read my post on that subject.
The process of exporting an existing certificate is thankfully straightforward.
First, open the Key Chain assistant and locate the certificate you want to export.
Click the small arrow beside it. This should expose the Private Key component. If this is missing, your certificate is not complete.
Select both of these rows and right click.
Choose “Export 2 items…” – Don’t worry, it will only generate one file. You’ll then be promoted for a password for your Private Key.
You now have the exported certificate. Copy the file onto the Windows machine you want to import it to. Double click on the file to launch the import wizard. This certificate should now be ready to use!