Using Email Encryption with Microsoft 365

Email encryption is available with Microsoft 365 Premium and Microsoft Office 365 E3 subscriptions as standard. For other plans such as Microsoft Exchange Plan 1 and Microsoft Business Standard, it is available as an additional per-mailbox license.

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 is 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

Sending an encrypted email

You can encrypt an email as required from the New Email screen in Outlook.

Create your email as normal but before sending, select the Encrypt button from the Options tab at the top of the screen.

This will give you the option to Encrypt Only or Do Not Forward.



This will encrypt the email message. Once received by the recipient, they are free to download attachments, print the email, forward it etc.

Do Not Forward

This option will encrypt the email and also prevents the recipient from printing or forwarding the email. This also applies to any Microsoft Office documents which are attached to the email. Other file formats will not be protected.

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.