By digitally signing a message, you apply your unique digital mark to the message. The digital signature (digital signature: An electronic, encryption-based, secure stamp of authentication on a macro or document. This signature confirms that the macro or document originated from the signer and has not been altered.) includes your certificate (certificate: A digital means of proving your identity. When you send a digitally signed message you are sending your certificate and public key. Certificates are issued by a certification authority, and like a driver's license, can expire or be revoked.) and 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.). This information proves to the recipient that you signed the contents of the message and not an imposter, and that the contents have not been altered in transit. For additional privacy, you can also encrypt messages.
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Digitally sign an individual message
- In the message, on the Message tab, in the Options group, click the Digitally Sign Message button .
Note If you don't see this button, click the Options Dialog Box Launcher in the lower right corner of the Optionsgroup to open the Message Options dialog box. Click the Security Settings button and in the Security Properties dialog box, select Add digital signature to this message. Click OK and then close the Message Options dialog box.
- Compose your message and send it.
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Digitally sign all messages
To change additional settings, such as choosing a specific certificate to use, click Settings.
Click OK twice.
- On the Tools menu on the Outlook Mail view, click Trust Center to open the Trust Center dialog box, and at the far left of the dialog box, click E-mail Security.
- Under Encrypted e-mail, select the Add digital signature to outgoing messages check box.
- If available, you can select one of the following options:
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