Encrypt email in Outlook 365 (Windows)


Instructions for encrypting email in Office 365 in Windows



When you need to protect the privacy of an email message, encrypt it. Encrypting an email message in Outlook means it's converted from readable plain text into scrambled cipher text. Only the recipient who has the private key that matches the public key used to encrypt the message can decipher the message for reading. Any recipient without the corresponding private key, however, sees indecipherable text. Outlook supports two encryption options:

1) S/MIME encryption - To use S/MIME encryption, the sender and recipient must have a mail application that supports the S/MIME standard. Outlook supports the S/MIME standard. This will be used for most professional communication that requires encryption, both internally and externally.

2) Office 365 Message Encryption (Information Rights Management), to use Office 365 Message Encryption, the sender must have Office 365 Message Encryption, which is included in Outlook 365 for University of Richmond faculty, staff, and student employees who have been granted access to Microsoft Exchange (Outlook).

Details / Instructions

1) Encrypting with S/MIME

This can be used for internal recipients and external recipients who use Outlook.

Before you start this procedure, you must first have added a certificate to the keychain on your computer. Once you have your signing certificate set up on your computer, you'll need to configure it in Outlook. Faculty, staff and student employees with Exchange (Outlook) access should already have a certificate, if yours is missing contact the Help Desk for assistance.

1.    Under the File menu, select Options > Trust Center > Trust Center Settings.

2.   In the left pane, select Email Security.

3.   Under Encrypted email, choose Settings.

4.   Under Certificates and Algorithms, click Choose and select the S/MIME certificate.

5.   Choose OK

6.  In an email message, choose Options, select Encrypt and pick Encrypt with S/MIME option from the drop down, you'll see an Encrypt with S/MIME if you have an S/MIME certificate installed on your computer.

If the recipient has a properly configured S/MIME certificate, they will be able to open and view your message. 

If you receive an error message when attempting to send an email encrypted with S/MIME encryption, your recipient most likely does not support this encryption method. 

2) Encrypting with Microsoft 365 Message Encryption

This can be used for external recipients that don't use Outlook or that otherwise have an issue opening your encrypted messages.

1. In an email message, choose Options, select Encrypt and pick the encryption that has the restrictions you want to enforce, such as Encrypt-Only or Do Not Forward.

2. The recipient will receive your email with a link to "read the message", when they open the message they will be asked to sign in with their Microsoft work or school account or obtain a one-time code. 


3. If they choose the one-time code they will receive an email from Microsoft Office 365 Message Encryption (MicrosoftOffice365@messaging.microsoft.com) with that code. 

4. The recipient will be able to view the encrypted message.

See Also



Article ID: 148810
Fri 1/19/24 2:02 PM
Thu 2/15/24 10:27 AM