Using Microsoft 365 Message Encryption

A simple guide for understanding, using, and knowing when to send encrypted email.

What Is Message Encryption?

Message Encryption protects sensitive email content so only the intended recipient can read it. It ensures:

• The message cannot be opened by unauthorized people
• The content cannot be forwarded (depending on the option you choose)
• Sensitive information stays secure inside and outside your organization

Encrypted messages work with:

• Outlook (Desktop, Web, Mobile)
• Gmail
• Yahoo
• Any email provider using a one‑time passcode

How Message Encryption Works

When you send an encrypted email:

1. Outlook encrypts the message before it leaves your mailbox.
2. The recipient receives a secure message notification.
3. They authenticate using:
   • Their Microsoft 365 account, or
   • A one‑time passcode sent to their email
4. Once authenticated, they can read the message securely.

You can choose different protection levels:

• Encrypt Only – The message is encrypted, but the recipient can forward it.
• Do Not Forward – The message is encrypted and cannot be forwarded, copied, or printed.
• Custom Sensitivity Labels – Your organization may provide additional options.

How to Send an Encrypted Email (Outlook Desktop)

1. Open a new email.
2. Go to the Options tab.
3. Click Encrypt.
4. Choose one of the available options:
   • Encrypt Only
   • Do Not Forward
   • Any custom label provided by your organization
5. Send your message normally.

How to Send an Encrypted Email (Outlook on the Web)

1. Go to https://outlook.office.com.
2. Create a new message.
3. Click the Encrypt button at the top.
4. Select your preferred encryption option.
5. Send your message.

How Recipients Open Encrypted Messages

Recipients will receive a message that says “You received an encrypted email.” They can open it by:

• Signing in with their Microsoft account, or
• Using a one‑time passcode sent to their email

No special software is required.

When Should You Use Message Encryption?

Use encryption whenever you send information that should not be publicly accessible, including:

• Client or customer information
• Legal documents
• Financial data
• Medical or personal information
• Passwords or access details
• Anything confidential or sensitive

If you’re unsure, encrypting is always the safer choice.

Tips for Using Encryption Effectively

• If the recipient says they cannot open the message, ask them to use the one‑time passcode option.
• Encryption works on mobile devices as well.
• You can combine encryption with Sensitivity Labels for additional protection.
• If you need to prevent forwarding, choose Do Not Forward.

Need Help?

If you have trouble sending or opening encrypted messages, contact your I.T. support team for assistance.