Encrypting an email message in Microsoft Outlook 2013 protects the privacy of the message by converting it from readable plain text into scrambled cipher text. Only the recipient who has the private key (private key: The secret key kept on the sender's computer that the sender uses to digitally sign messages to recipients and to decrypt (unlock) messages from recipients. Private keys should be password protected.) that matches the public key (public key: The key a sender gives to a recipient so that the recipient can verify the sender's signature and confirm that the message was not altered. Recipients also use the public key to encrypt (lock) email messages to the sender.) used to encrypt the message can decipher the message for reading.
A recipient without the corresponding private key will see this message, "This item cannot be displayed in the Reading Pane. Open the item to read its contents." If the recipient tries to open the item, a dialog box pops up saying "Sorry, we're having trouble opening this item. This could be temporary, but if you see it again you might want to restart Outlook. Your Digital ID name cannot be found by the underlying security system."
Encrypt a single message
- In message that you are composing, click Options.
- In the More Options group, click Message Options Dialog Box Launcher .
- Click Security Settings, and then select the Encrypt message contents and attachments check box.
- Compose your message, and then click Send.
Encrypt all outgoing messages
When you choose to encrypt all outgoing messages by default, you can write and send messages the same as with any other messages, but all potential recipients must have your digital ID to decode or view your messages.
- Click the File tab.
- Click Options.
- Click Trust Center.
- Click Trust Center Settings.
- On the Email Security tab, under Encrypted email, select the Encrypt contents and attachments for outgoing messages check box.
- To change additional settings, such as choosing a specific certificate to use, click Settings.