How to apply a signature to emails before encrypting them

Scenario

Your organization uses Office 365 Message Encryption (OME) to encrypt emails that contain sensitive information. You want to ensure that signatures are applied to the emails before they are encrypted and sent to the recipient.

Resolution

As long as the emails are not marked as 'Rights protected emails' in Outlook before being sent, (server-side) signatures can be applied to the emails by routing them to Exclaimer Cloud.

Once the emails have been processed by Exclaimer Cloud, they are returned to Exchange Online for delivery to the recipient. At this point, a mail flow rule to encrypt the emails can be applied to the emails.
To encrypt the email - you need to use a mail flow rule based on words in the email subject line.

To create a mail flow rule:

1. Sign in to the Exchange Online admin portal (https://admin.exchange.microsoft.com) as an Administrator.
   
   The Exchange admin center is displayed.
   
   
2. From the left-hand navigation menu, select Mail flow, then select Rules.
   
   
3. In Rules, you will see the Transport Rule you created when setting up Signatures for Microsoft 365. Click on the pencil icon.
   
   The required window is displayed. Ensure that the Stop processing more rules option is selected before you click Save.
   
   
   
   
4. Click the + icon, then click Create a new rule....
   
   
   The new rule window is displayed.
   
   
5. In Name, enter an appropriate name for the rule.
   
   
6. In Apply this rule if, select The sender is located...inside the organization.
   
   
7. In and, select The Subject includes...
   
   
8. In Do the following....select Apply Office 365 Encryption and rights protection to the message with...
   
   NOTE: Make sure you select the Encrypt template.
9. Select the Defer the message if rule processing doesn't complete option.
   
   

Once these changes are in place, you need to make sure that the email to be encrypted consists of the specified word(s) on the mail flow rule, in the email subject line.

Example:

NOTES:

- The email will only be encrypted after it is processed by Exclaimer Cloud.
Example:


- The signature will only be applied to the first email in the chain as any further replies will already be encrypted before being processed by Exclaimer Cloud.