Email Encryption with Microsoft Office 365

What is Office 365 Message Encryption

  • Encrypts messages sent to internal or external recipients.
  • Allows users to send encrypted messages to any email address, including, Yahoo! Mail, and Gmail.
  • Encryption Portal can be customized with your company branding*.
  • Microsoft securely manages and stores the keys, so you don’t have to.
  • No additional software is needed as the encrypted message (sent as an HTML attachment) can be opened in a browser.

When should encryption be used?

Encrypting all emails is not generally necessary – it is recommended to use encryption when you want to send sensitive business information to people outside your organization, whether they’re consumers or other businesses. Examples of such material includes and is not limited to:

  • Bank / Credit Card Details
  • ID documents / information
  • Legal documents / information

Enabling Office 365 Message Encryption

Microsoft Office 365 Message Encryption is included with Enterprise E3 plans and above. For other plans such as Exchange Plan 1 and Business Premium, this feature is licensed separately on a per-mailbox basis. Each user wishing to use this feature must have a license.

Sending an Encrypted Email

Once Office 365 Message Encryption has been enabled for your organization, you can send one-off encrypted emails by prefixing your email subject with ENCRYPT: (including the colon)

Send the message as normal and it will be encrypted automatically

If you have a requirement to encrypt all emails sent to a certain company/contact – we can setup a rule to apply this automatically without you having to use the subject prefix.


‘Do Not Forward’ option

During email transmission, attachments are encrypted. Once the recipient decrypts the email, they are free to download the attachment, print it, forward it etc
To prevent this the DO NOT FORWARD option encrypts the email and prevents the recipient from printing or forwarding the email.

This protection also applies to any Microsoft Office documents (Word, Excel, PowerPoint etc) which are attached to the email.

With PDF attachments, the email has the additional protection but the attachment does not.


How to open an Encrypted email

To view encrypted messages, recipients can either get a one-time passcode, sign in with a Microsoft account, or sign in with a work or school account associated with Office 365. Recipients can also send encrypted replies.

They don’t need an Office 365 subscription to view encrypted messages or send encrypted replies.

The recipient will get a message that they have a protected message available to them. They will need to click the ‘Read the message’ button or open the html attachment.

The recipient will be directed to a logon page where they must log in using their email credentials or a one-time passcode which is emailed to them
Once the recipient has accessed the encrypted email, they can send an encrypted reply


What to do next

If you have a requirement for encrypted emails, please contact us at 703 9910101 Ext. 9 and we will advise you if additional licensing is required. Implementation of this feature can take up to 48 hours. Customized branding of the encryption portal will be charged extra.