The following is tip #16 from "20 Tips on securing Outlook in 20 minutes," excerpted from a chapter in Paul Robichaux's book, Secure Messaging with Microsoft Exchange Server 2003 © 2004, published by Microsoft Press. Return to the main page for more tips on this topic.
Actually signing or encrypting messages is easy with Outlook. You can always sign or encrypt individual messages, either using the Outlook toolbar or by opening the message properties; you can also tell Outlook to sign or encrypt all messages by default.
Encrypting or Signing a Single Message
To secure a message as you're composing it, open the message's Properties dialog box and click the Security tab. The Encrypt Message Contents And Attachments and Add Digital Signature To This Message check boxes do just what you'd expect; you can select either or both of them to add protection to your message when it's sent. When signing a message, you have two additional options: you can clear-sign the message (so that non-S/MIME-aware mail software can display the message contents), and you can request a signed return receipt -- this proves that the recipient opened the message at a particular date and time, because it's signed with the recipient's private key.
You can also use this dialog box to choose a set of S/MIME parameters for the message; your choices are taken from the sets of S/MIME settings you defined on the Security tab of the Options dialog box, as discussed in the preceding section. You can also set a security label from this dialog box, but you won't be able to do so unless you're using a policy module, and there aren't any widely available ones except those used with DMS.
Updating the Outlook Toolbar
Outlook's Standard toolbar includes toolbar buttons for encrypting and signing the current message, but they're not visible by default. Fortunately, you can customize the toolbar to include the icons—just use the Tools | Customize command, which displays the Customize dialog box. Here's what to do:
- Open a message (new or old, it doesn't matter). If the toolbar you want to put the buttons on isn't visible, make it visible with the View | Toolbar submenu.
- Choose the Tools | Customize command. When the Customize dialog box opens, click the Commands tab.
- Select Standard in the Categories list. The Commands pane lists the available toolbar buttons. Near the bottom of the Commands list, you'll see two icons: Encrypt Message Contents And Attachments and Digitally Sign Message.
- Drag the icons to the desired positions on the toolbar.
- Click Close.
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About the author: Paul Robichaux is a partner at 3sharp LLC, author of several books on Exchange, Windows, and security, a Microsoft MVP for Exchange Server and a frequent speaker and presenter at IT industry conferences. He's written software for everyone from the US National Security Agency to scientists flying their experiments aboard the Space Shuttle, fixed helicopters in the desert and spent way too much time playing video games.