Trinity Email Encryption

You can send encrypted mail directly from your Trinity account when you need to protect sensitive details. Encryption limits who can read the message and helps prevent unauthorized access.

When you should use it

Use encryption when you share anything that contains personal data, financial details, student records, or information you don’t want forwarded. Encryption in Microsoft 365 is a security feature that protects emails, files, and data (not subject lines) by converting information into an unreadable format. Only authorized users with the correct decryption key can access the content, ensuring confidentiality and compliance.

Why send an encrypted email?

People sometimes use email to exchange sensitive information, such as financial data, legal contracts, confidential product information, sales reports and projections, or customer and employee information. With Microsoft 365 Message Encryption, encrypted email messages can be sent between people inside and outside of the college. Microsoft 365 Message Encryption works with Outlook.com, Yahoo!, Gmail, and other email services. Email message encryption helps ensure that only intended recipients can view message content.

What is the tradeoff when sending an encrypted email?

Encrypted email adds an extra layer of security to the message, but may also require additional steps for the recipient to view it. Encrypted email messages can be read directly in Outlook on the web (OWA), in Outlook for iOS and Android, and in Outlook for Windows versions 2019 and Microsoft 365. Other email clients will see a message with a link. That link will take Microsoft 365 users to OWA to read the message. Users with other email accounts will be prompted to obtain a one-time passcode and read the message in a browser window.

For more information on message encryption, see: Send, view, and reply to encrypted messages in Outlook for the PC

Encryption Options

Outlook for Windows, Outlook for Mac, and Outlook on the web provide several encryption options:

Encrypt-Only – The message is encrypted in transit and at rest in the recipient’s mailbox, including any attachments. Recipients cannot remove the encryption, so forwards and replies to the message remain encrypted.
Do Not Forward – The message is encrypted in transit and at rest in the recipient’s mailbox, including any attachments. Recipients can read this message but cannot forward, print, or copy content. The conversation owner retains full access to their messages and all replies.
Confidential – The message is encrypted in transit and at rest in the recipient’s mailbox, including any attachments. This content is proprietary information intended for internal (Trinity) recipients only. External recipients will not be able to open the message.
Confidential View Only – The message is encrypted in transit and at rest in the recipient’s mailbox, including any attachments. This content is proprietary information intended for internal (Trinity) recipients only. External recipients will not be able to open the message. Additionally, this content cannot be modified, copied, or printed.

Additional Notes:

Avoid putting sensitive information in the subject line. Subject lines are never encrypted.
Recipients outside Trinity may need to verify their identity or register before they can open an encrypted message. Let them know ahead of time so they know what to expect.
Attachments up to 150 MB can be sent, depending on the recipient’s mailbox limits.
Office documents can be restricted from being copied, printed, or forwarded when using Do Not Forward.
Encrypted messages and attachments do not expire for the recipient.

Sending encrypted emails

Create a new message
Click Options -> Encrypt -> there are four options
- Encrypt-Only
- Do Not Forward
- Confidential
- Confidential View Only
Select which option you would like

Microsoft Outlook 2021, 2019, 2016, and 2011 – (Source Info)

Create a new message
Click the Taskbar and select Drafts -> Encrypt -> there are four options
- Encrypt-Only
- Do Not Forward
- Confidential
- Confidential View Only
Select which option you would like

For Outlook for Mac 2019, 2016, and 2011 – (Source Info)

Create a new message
Click the menu bar ellipses (…) -> Encrypt -> there are four options
- Encrypt-Only
- Do Not Forward
- Confidential
- Confidential View Only
Select which option you would like

Microsoft support article (How do I open a protected message)

Encryption Option	Attachment Type	Recipient’s Email Service and Client
Encryption Option	Attachment Type	Trinity College Outlook.com and Microsoft 365 Accounts	Non-Trinity College Outlook.com and Microsoft 365 Accounts	Mail Services Other Than Outlook.com and Microsoft 365 Accounts
Encrypt-Only	Microsoft Office attachments (e.g., Word, Excel, PowerPoint files)	Attachments can be downloaded without encryption.	Attachments can be downloaded without encryption.	A Microsoft encryption-compliant client or temporary passcode is required to access the email and download attachments from the Microsoft 365 Message Encryption portal.
Encrypt-Only	Other attachment types	Attachments can be downloaded without encryption.	Attachments can be downloaded without encryption.	A Microsoft encryption-compliant client or temporary passcode is required to access the email and download attachments from the Microsoft 365 Message Encryption portal.
Do Not Forward	Microsoft Office attachments (e.g., Word, Excel, PowerPoint files)	Encrypted Office attachments can be opened in Microsoft Office across platforms. If the attachments are downloaded and sent to another recipient, the recipient will not be able to open the attachments, but has the option to request access.	Encrypted Office attachments can be opened in Microsoft Office across platforms. If the attachments are downloaded and sent to another recipient, the recipient will not be able to open the attachments, but has the option to request access.	A Microsoft encryption compliant client or temporary passcode is required to access the email and download attachments from the Microsoft 365 Message Encryption portal. Encrypted Office attachments can be opened in Microsoft Office across platforms. If the attachments are downloaded and sent to another recipient, the recipient will not be able to open the attachments but has the option to request access.
Do Not Forward	Other attachment types	Attachments can be downloaded without encryption.	Attachments can be downloaded without encryption.	A Microsoft encryption compliant client or temporary passcode is required to access the email and download attachments from the Microsoft 365 Message Encryption portal. Attachments can be downloaded without encryption.
Confidential	Microsoft Office attachments (e.g., Word, Excel, PowerPoint files)	Attachments can be downloaded but cannot be opened unless the recipient is signed into Office 365 with a Trinity College account.	The recipient cannot access the email.	The recipient cannot access the email.
Confidential	Other attachment types	Any user can open attachments without restriction.	The recipient cannot access the email.	The recipient cannot access the email.
Confidential View Only	Microsoft Office attachments (e.g., Word, Excel, PowerPoint files)	Attachments cannot be opened unless the recipient is signed into Office 365 with a Trinity College account. The recipient cannot edit or save the document with Microsoft Office.	The recipient cannot access the email.	The recipient cannot access the email.
Confidential View Only	Other attachment types	Any user can open attachments without restriction.	The recipient cannot access the email.	The recipient cannot access the email.