Feb 19, 2025
This article will walk you through Signing & Encrypting e-mail in Outlook 2013.
Note: Provided you have a client digital certificate, you can digitally sign an e-mail to any recipient. Digitally signing a message with the settings specified in prerequisite #3 will also send the recipient your public key. The recipient can then use your public key to send you an encrypted message. This message can only be decrypted with your private key which should never leave your system. In order to send an encrypted message to someone else, you will first need a signed e-mail from them; in turn you can use their public key to send them an encrypted message that only they can read.
Before you are able to sign and/or encrypt e-mails in Outlook, you must first:
Note: When you add or update a contact directly from a signed e-mail, Outlook will pull in the sender's public key and associate it with the contact details. Now when you try and send an encrypted e-mail, it will know what certificate to use for the recipient.
Now that you have the public key of the intended recipient saved, you can compose an e-mail and use the Encrypt feature.
When you reissue or renew your GlobalSign certificate, you will get a unique keypair each time. This means that the new certificate will not be able to decrypt past e-mails that were encrypted with your old certificate. For this reason, make sure you keep your old certificates installed on your computer. Even if they are expired, they still have the functionality to decrypt your old e-mails.
Check your certificate installation for SSL issues and vulnerabilities.