Sending and Receiving Encrypted Emails

While email is not the preferred platform to share sensitive data, safely sharing important information through email is possible with Office365 email encryption.  By following a few easy steps, your email can be transmitted to another person safely and securely.

In this Article

Why use Encryption?

Although email is an effective and convenient means of communication, it provides no inherent security for its contents.  If email messages are somehow intercepted in-transit or otherwise compromised by an attacker, the email contents can be viewed openly.  Encryption provides a method to effectively “scramble” the contents of the message so that only the intended recipient can read it.  Therefore, it is vital that any sensitive data that must be sent through email (SSNs, student records, etc.) should be encrypted.

Overview of Office365 Encryption

Outgoing emails can be encrypted by setting two simple options prior to sending.  These are the message “Importance” and “Sensitivity”.  Instructions on how to set these options are in the Sending an Encrypted Email sections of this guide.

Once “Importance” and “Sensitivity” are updated correctly, the intended recipient will receive an email notifying them that encrypted content is waiting for them.  They do not receive the contents of the original email in their inbox, but will instead receive instructions on how to retrieve the contents of original email.  Once authentication has been provided, the original content (including attachments) is securely revealed.

Sending an Encrypted Email with Outlook (Windows)

  1. Start a new email as you normally would.
  2. With the "Message" tab active, click the small “open” icon at the bottom of the "Tags" section.  This will open the Message Properties.

Microsoft Outlook Tags Section

  1. Set the "Importance" dropdown to “High”, and the "Sensitivity" dropdown to “Confidential”.

Outlook Message Properties

  1. Click "Close", then finish composing and sending your email as you normally would.


Sending Encrypted Email on a Mac

Due to some unique considerations with both the 2011 and 2016 versions of Outlook on Mac, it cannot be used to send encrypted emails.  If you are a Mac user, you should use NKU Webmail to send encrypted emails.  While Macs cannot send encrypted emails, they are still able to receive them.



Sending an Encrypted Email with NKU Webmail

  1. Start a new email as you normally would.
  2. Click the small ellipsis icon next to “Discard” in the ribbon, then click "Set importance" > "High".

Outlook email options menu

  1. Click the icon again, then select "Show Message Options".
  2. Set "Sensitivity" to “Confidential”, then click "OK".

Outlook Message options dialog box

  1. Finish composing and sending your message as you normally would.

Reading an Encrypted Email

When you receive an encrypted email, it will not contain the actual message, but rather instructions on how to retrieve the message.

  1. An encrypted email will contain an attachment named “message.html”.  Open this attachment.

An encrypted email message.

  1. A browser window will display, prompting you to sign in or use a one-time passcode.  NKU users can use “Sign in”, and non-NKU users should use “Use a one-time passcode”.

Encrypted email message options.

Using the "Sign in" method

  1. The page will prompt you for which account you would like to sign in with to view the message.  Choose “Work or school account”.

Dialog box prompting user to select an account to view an encrypted message.

  1. If prompted, log in with your NKU username and password.  This will sign you into Office 365.
  2. The message (and any attachments) will then appear in an unencrypted format.
  3. You will be also be able to reply to the message using the "Reply All" button in the upper right corner.  Replying this way will also encrypt your message.  There is also an option to forward the email, which will also be encrypted.


Using a One-Time Passcode

  1. Users that choose this method will receive an additional email containing a passcode.  Copy/paste or enter this passcode into the passcode box that appears on page, and click "Continue".  After doing this, the message will then appear in an unencrypted format.

An Office 365 dialog box containing a one-time passcode.

Reading an Encrypted Email Using a Phone or Tablet

  1. If you receive an encrypted message on your phone or tablet, you will need to have the OME Viewer app installed.  A link to download the app (for both Apple and Android devices) will be provided in the email.

An encrypted email message viewed on a phone.

  1. After downloading the app, you may go back to the “message.html” attachment, tap on it, and open it in OME Viewer.




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Article ID: 126682
Thu 1/28/21 11:11 AM
Thu 1/28/21 11:50 AM