Configuring Thunderbird To Use Your New S/MIME Certificate

Your certificate is installed in Thunderbird. You need to map the certificate to your e-mail account.

  1. Open Thunderbird
  2. From the Tools menu, select Account Settings (if you are using Mac OS X select Account Settings from the Edit menu)
  3. Expand the menu for the account you would like to add security to.
  4. Select Security from the expanded account menu.
  5. In the Digital Signing box, click the Select button.

  6. Choose the imported certificate and click OK.
    NOTE 1: If you have had an S/MIME certificate before look for the USERTRUST Network certificate.
    NOTE 2: If you have had other USERTRUST Network certificates before choose the one with the highest ID number.

  7. You will be presented with a dialog box suggesting that you specify a certificate for other people to use when sending you encrypted e-mail messages. Click OK, to use the same certificate.
  8. Click OK.
  9. Check the Digitally sign messages (by default) checkbox in the Digital Signing area. This will configure your mail client to digitally sign all outgoing e-mail messages by default.
  10. Check the Never (do not use encryption) radio button in the Encryption area. this will make encryption optional on outgoing e-mail messages.

  11. Click OK, to complete the configuration of your account.

Congratulations, your outgoing e-mail will now be digitally signed by default. Test this by sending yourself a message. Now would be a good time to delete the downloaded certificate bundle (.p12 file), if you haven’t already.