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If you have a digital certificate, you can use it to digitally sign and encrypt emails. IdenTrust digital certificates that can be used for this application include:

  • DoD ECA certificates
  • IdenTrust TrustID® certificates
  • IdenTrust Global Common (IGC) certificates

To install your digital certificate into Microsoft Outlook for Mac to digitally sign or encrypt emails, follow these instructions:

  1. Make sure that you have imported your certificate into the Mac OS X keychain.
  2. Open Outlook.
  3. In Outlook, select the “Tools” menu. Then choose “Accounts
  4. Highlight your “Mail Account” and click the “Advance” button.
  5. Click the “Security” tab.
  6. In the “Digital Signing” area, click the “Certificate Pop-Up” menu option. (Please note the “Certificate Pop-Up” menu only displays certificates that are valid for digital signing or encryption that you have already added to the keychain for your Mac OS X user account.)
  7. Select your “Digital Signing” certificate from the list. This typically displays as your first name and last name.
  8. Click “Choose”.
  9. Select “Signing Algorithm SHA-1
  10. Once you have selected your certificates, set the following options:
    • Select “Sign outgoing messages”.
    • Select “Send digitally signed messages as clear text”. This ensures that recipients can read your signed messages. It is especially important if your recipient is using a web-based or mobile mail client.
    • Select “Include my certificates in signed messages”. This option includes your public encryption key so that someone else can use it to send you encrypted messages.
  11. In the “Encryption” area, click the “Pop-up Menu” option.
  12. Select your “Encryption Certificate” from the list. This typically displays as your first name and last name.
  13. . Select “Encryption Algorithm 3DES”.
  14. In the “Encryption Area” we recommend that you do NOT select the option to “Encrypt Outgoing Messages and Attachments” by default. IdenTrust recommends that you manually choose encryption for individual messages rather than choosing it by default.
  15. Click “OK” to close the “Edit Accounts” dialog box and then close the “Accounts” window
  16. Send an email to yourself as a test. Based on the options you selected, when you compose new messages, Outlook shows “a lock” and one of three options:
    • This message will be Digitally Signed
    • This message will be Encrypted
    • This message will be Digitally Signed and Encrypted
  17. To change the options on a message-by-message basis, when you are composing a new message, click the “Options” tab, click “Security” and then click “Encrypt Message”, “Digitally Sign Message” or select “both".