To send a message with encryption, compose a new message, select the Options ribbon, and then select Encrypt. You can choose Encrypt or Do Not Forward.

Read an encrypted email message using Outlook.com or Microsoft 365

If you’re using Outlook.com or Microsoft 365 with new Outlook, Outlook for Mac, Outlook.com, or the Outlook mobile app, you can read and reply to encrypted messages the same way you do with unencrypted messages.

If you’re using 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 account or your Microsoft 365 account.

Read an encrypted email message without 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 an email.

Attachments are 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 new Outlook. 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 Do Not Forward 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 a 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.