Outlook: Encrypting Email Messages and Attachments

Sensitive data, should not be sent via unencrypted Email, whether written in the body or as an attachment. Unencrypted Email is sent in clear text that can easily be intercepted and read by anyone, while in transit.

Examples of Sensitive Data:

  • Social Security numbers

  • Driver’s License numbers

  • Passport numbers

  • State-issue ID numbers

  • Any bank/financial account numbers

  • Credit/debit card numbers

  • Protected health information

  • Documents protected by attorney-client privilege

  • Any passwords or authentication credentials

Use the instructions, on this page, to encrypt the body of Email messages, as well as attached files.

Encrypt Using they Encrypt Button

Outlook Desktop Version and Outlook on the Web offer an Encrypt button while composing a new email message.  When pressed, the button triggers that the email message and attachments become encrypted.  Two options that are available from the Encrypt button are to, simply encrypt the message and attachments, or to encrypt and also prevent forwarding of the message.  Instructions, as well as more information on the two options is available at this Microsoft Support Page.

Outlook on the Web.  Click Options, then Encrypt.  Select Either Encrypt or Do Not Forward.

Outlook on the Web View

Outlook Desktop Version.  Click Options, then Encrypt.  Select Either Encrypt or Do Not Forward.

Outlook Desktop Version View


Encrypt Using 7-Zip

This method is for encrypting attached files only, not the email message itself.

After the message is sent, the user receiving the message will download an attached ZIP file and open it using the password you supply to them.

ITD Lab How-To Video

Install 7-Zip

Before installing, check if 7-Zip is already installed on your computer.

  1. Click on the Start Button on your SVSU computer and Type Software Center (note there is no dialog box, just start typing).  You will see a dialog box similar to the one below - click on Software Center.

  2. Software Center will open and you will see a screen similar to the one below - click on 7-Zip and then click Install in the next dialog box.  7-Zip will be installed.

    If you do not see 7-Zip please open a ticket at mysupport.svsu.edu.  Ask for assistance with running Configuration Manager with the following at the ticket description.  "I'm trying to install 7-Zip and it does not show Software Center.  I need assistance running Control Panel > System Security > Configuration Manager > Actions > Machine Policy Retrieval & Evaluation Cycle.  Please assign this ticket to Technical Support per the Encrypting eMail Attachments Knowledge Article".  A technician will contact you and assist in getting 7-Zip on Software Center for you.


Encrypt Files

  1. Open File Explorer on your computer.
  2. Select the files that you want to send as encrypted files by holding down the CTRL button and clicking to select multiple files.
  3. Release the CTRL button and Right Click within the highlighted, selected files, select 7-Zip, then Add to Archive
  4. Set the following items in the dialog box to these values (i.e. leave all defaults except those listed below)
    1. Change the Filename and location of where you want the file to be stored.  The ... buttons allow you to select the storage location.  The white dialog box is the file name.
    2. Archive format -  zip
    3. Encryption method -  ZipCrypto
    4. Enter the password 
    5. Reenter the password
    6. Click OK
    7. The zipped file will be stored in the location you specified in the first bullet above.
    8. The encrypted zip file can now be attached to an email.
    9. If the receiver has an up to date Windows they will be able to decrypt it with windows explorer without needing to have 7-zip installed.
    10. You will need to provide them the password that you created when you encrypted the file.
  5. The user will receive the file in their email.  They will need to download the file and open it using the password you supplied them.


Article ID: 103527
Mon 3/30/20 10:06 AM
Tue 3/7/23 10:47 AM

Related Articles (3)

Encrypt documents containing sensitive information.
Frequently asked questions specifically regarding Outlook Desktop Version.
Frequently asked questions specifically regarding Outlook on the Web.