How to Send Encrypted Emails (Mimecast Secure Messaging)

Summary

This article explains how to send secure, encrypted emails containing sensitive information (PII, PHI, financial data) using the Mimecast Secure Messaging Portal

Body

Overview 

Standard email is not secure. If you need to send sensitive data to an external recipient, you must use Mimecast Secure Messaging. This ensures the message is encrypted and the recipient must log in to a secure portal to read the message and download attachments.

How to Send an Encrypted Email

The easiest way to trigger encryption is by using a specific keyword in your Outlook subject line.

  1. Open Outlook and compose a New Email.
  2. Draft your email and attach any necessary files.
  3. Crucial Step: In the Subject Line, type the following text exactly as shown:[secure]

    subject line in outline outlining [secure] tag line
     
  4. Click Send.
     

Alternative Method:

Another method to sending encrypted emails is by logging into the Single-Sing-On (SSO) portal. 

  1. Once logged in to the SSO portal, locate and click the Mimecast Secure Message Portal tile.

    Mimecast Secure Message Portal tile
     
  2. You'll be directed to enter your WWCC email address.

    Walla Walla Community College Enter Log In Email Address prompt
     
  3. Once in the Secure Email portal, you'll be able to select Compose and enter the recipients, body of message and then choose Send.

    WWCC Secure message portal Compose, To, body of email, and Send fields
     
  • Finally, once you select Send, a drop-down window will prompt to select the type of recipients. 

    Secure Messaging Options dropdown

    NOTE: 
    All Recipients: External and internal recipients will receive the same experience. 
    External Recipients: If you have a mix list of recipients (internal and external) this choice will only send the following screen to external recipients.

    WWCC sent you a secure message window


     

What the Recipient Sees

It is helpful to know what your recipient will experience so you can advise them if they have questions.

  1. The recipient will receive a notification email in their standard inbox. It will not contain the body of your message or attachments.
  2. The email will say "You have a new Secure Message" and provide a link to the portal.

    walla walla community college Mimecast secure message

     
  3. When they click the link, they will be taken to the Secure Message Portal.
    • First-time users: Will be asked to create a password.
    • Returning users: Will simply log in with their email and existing password.
  4. Once logged in, they can read your email, download attachments, and reply securely.

Important Best Practices

  • Attachments: Attachments are fully encrypted when sent via this method.
  • Replies: If the recipient replies via the portal, their response to you will also be secure.

Need Help?

If you are having trouble sending a secure message or your recipient is unable to access the portal, please submit a support ticket.

Details

Details

Article ID: 18403
Created
Thu 12/11/25 1:25 PM
Modified
Wed 12/17/25 5:09 PM