The new Microsoft 365 Message Encryption capabilities make it easier to share protected emails with anybody—inside or outside your organization.

Protect sensitive emails using the integrated encryption system in Office 365.

  • Help reduce the risk of unintended disclosure by encrypting and rights-protecting email messages sent both inside and outside your organization.
  • New! Send encrypted and rights protected messages to people inside and outside your organization (including users of Office 365, non-Office 365 email applications, and web-based email services such as Gmail.com and Outlook.com) with Do Not Forward or custom Rights Management Services templates to enable B2B and B2C scenarios.
  • Send encrypted email messages to anyone, regardless of their email address.
  • Provide strong, automated encryption with a cost-effective infrastructure.
  • Eliminate the need for certificates and use a recipient’s email address as the public key.
  • Communicate through a Transport Layer Security-enabled network to further enhance message security.
  • Enhance the security of email responses by encrypting each message in the thread.

How to send an encryted email using the Outlook desktop application:

If you are a Microsoft 365 subscriber, here is a quick guide to encrypting an emaul sent from the Outlook desktop application:

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.

Outlook - Encrypt Email

How to send an encryted email using the Outlook web application:

The Microsoft 365, Outlook app now includes encryption features that let you share your confidential and personal information while ensuring that your email message stays encrypted and doesn’t leave Microsoft 365. This is useful when you don’t trust the recipient’s email provider to be secure.

The encryption options are available in the ribbon when you’re composing a message.

How do I read an encrypted email message? (I’m using Microsoft 365)

If you’re a Microsoft 365 user and using the Outlook web app, the Outlook mobile app, or the Mail app in Windows 10, you can read and reply to encrypted messages the same way you do with unencrypted messages.

If you’re using Outlook for Windows, Outlook for Mac, or a third-party email app, you’ll receive an email message with instructions for how to read the encrypted message. You can gain access using your Microsoft 365 work account.

How do I read an encrypted email message? (I’m not using Outlook.com or Microsoft 365)

You’ll receive an email message with instructions for how to read the encrypted message. If the encrypted message was sent to a Google or Yahoo Mail account, you can authenticate using your Google or Yahoo account or by using a temporary passcode. If the message was sent to a different account (Comcast or AOL, for example) you can use a temporary passcode. The temporary passcode will be sent to you in email.

Are attachments also encrypted?

All attachments are encrypted. Recipients who access the encrypted email via the Office Message Encryption portal can view attachments in the browser.

Attachments behave differently after they’re downloaded depending on the encryption option used:

If you choose the Encrypt option, recipients with Outlook.com and Microsoft 365 accounts can download attachments without encryption from Outlook.com, the Outlook mobile app, or the Mail app in Windows 10. Other email accounts using a different email client can use a temporary passcode to download the attachments from the Microsoft 365 Message Encryption portal.

If you choose the Encrypt and Prevent Forwarding option, there are two possibilities:

  • Microsoft Office attachments such as Word, Excel or PowerPoint files remain encrypted even after they’re downloaded. This means that if the recipient downloads the attachment and sends it to someone else, the person they forwarded it to won’t be able to open the attachment because they don’t have permission to open it.

    Note that if the recipient of the file is using an Outlook.com account, they can open encrypted Office attachments on the Office apps for Windows. If the recipient of the file is using an Microsoft 365 account, they can open the file in Office apps across platforms.

  • All other attachments, such as PDF files or image files, can be downloaded without encryption.