Microsoft O365 Email Encryption

ITS will be utilizing O365 encryption, a message-encrypting tool built into Microsoft Office 365.

What is Microsoft O365 Email Encryption?

Specifically, Microsoft O365 message encryption enables users to securely send email messages to users inside and outside of UofL on any device. O365 email encryption enables email security essential to some UofL operations due to the sensitivity of data shared.

 Capabilities of Encryption

O365 is capable of the following:

  • Encrypting email messages, either on the sender’s machine or via a central server while the message is in transit

  • Decrypting messages to the recipient

  • The recipient’s machine uses a key to decrypt the message, or a central server decrypts the message on behalf of the recipient after recipient identity validation occurs


What does “Encrypting an Email” mean?

O365 encryption:

  • Transforms the message from plain text in to unreadable ciphertext

  • Keeps the message in ciphertext while in transit to protect the message from being read if intercepted

  • Decrypts the message via a key or authenticated response

How to Encrypt an Email

How to Tell an Email is Encrypted

"Do Not Forward" Feature


Microsoft has provided the following resources/documentation for users to review regarding O365 encryption and message security: