Before you can sign or encrypt messages, you need to specify the default Digital ID in Outlook Express.

To specify a default Digital ID:

1. In the main Outlook Express window (not a message window), choose Tools > Accounts from the menu.
2. Select the mail account you want to send secure e-mail from, and then click Properties.
3. On the Security tab, select the check box labeled Use a digital certificate when sending secure messages from, and then click the Digital ID button.
4. Select the Digital ID you want to use with this account and then click OK.