Sometimes you want additional protection for your e-mail communication to keep it from unwanted eyes. Encrypting an e-mail message in Microsoft Office Outlook 2007 protects the privacy of the message by converting it from (readable) plaintext into (scrambled) ciphertext. 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) e-mail messages to the sender.) used to encrypt the message can decipher the message for reading. Any recipient without the corresponding private key would see only garbled text.
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Encrypt a single message
- In the message, on the Message tab, in the Options group on the ribbon, click the Encrypt Message Contents and Attachments button .
Note If you don't see this button, click the Options Dialog Box Launcher in the lower right corner of the group to open the Message Options dialog box. Click the Security Settings button and in the Security Properties dialog box, select Encrypt message contents and attachments. Click OK and then close the Message Options dialog box.
- Compose your message and send it.
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Encrypt all outgoing messages
Choosing to encrypt all outgoing messages means, in effect, your e-mail is encrypted by default. You can write and send messages the same as with any other e-mail messages, but all potential recipients must have your digital ID to decode your messages.
- On the Tools menu, click Trust Center, and then click E-mail Security.
- Under Encrypted e-mail, 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.
- Click OK twice.
Note 3DES (3DES: An encryption algorithm based on the Data Encryption Standard (DES). Triple DES (3DES) repeats DES three times. Consequently, 3DES runs slower than standard DES. However, it is more secure.) is the default encryption algorithm used in Outlook 2007. For more information, see the Overview of certificates and cryptographic e-mail messaging in Outlook.
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