joar.com > Using encryption and digital signatures in Mail:
“Q: The keychain will not import a certificate because “The specified item already exists in the keychain”.
A: This is most likely because the certificate about to be added has the same email address as a certificate already in the Keychain. Inspect the imported certificates in the Keychain Access application to verify if this is the case or not.
If you have certificates for more than one email address, you possibly requested and, or downloaded the same certificate more than once.
Also, you might be exporting a certificate file from Mozilla with more than one certificate, where the Keychain already contains an identical certificate. “
Now, I had a couple of problems with this since all my keys are currently labelled as “Thawte Freemail Member.” But as you can see in the bottom pane, it’s possible to see what email address you’ve associated with a given key.
Toggle the “trust settings” widget . . . .
The step-by-step tutorial offered here is well worth reading. I think his idea of linking .Mac accounts with a certificate is a great idea and a good way to get this idea into more widespread, ie, not just for geeks, use.
[Posted with ecto]