Password Protect and Encrypt Your Email in Windows

Secure your email data with your Windows password and encryption

If other people use your computer and you're worried they could read your emails, you can set up a distinct Windows account for each user so emails and documents are kept separate. But, that's not enough to protect your emails. Your best bet is to encrypt them.

Encrypting an email message usually means converting it from readable plain text into scrambled cipher text. Only the recipient, who has the private key matching the public key used to encrypt the message, can decipher it. Anyone who doesn't have the key only sees garbled text. 

How to Protect Your Emails

All emails sent using Gmail, Outlook, or iOS can be encrypted by default. When you encrypt all outgoing messages by default, you compose and send emails as you normally would, but recipients need a digital ID or passcode to view them. Here's how to add this extra layer of security in Gmail and Outlook.


Gmail's encryption is called Confidential Mode. You can toggle it on or off by clicking the lock icon at the bottom of a new message. From here, you can set an expiration date and a passcode. The passcode can be sent to either a person's email or via text.

Screenshot of Gmail's Confidential Mode options


In Outlook, you can choose to encrypt a single message or encrypt all outgoing messages.

  • To encrypt a single message: Select File > Properties > Security Settings and click the Encrypt message contents and attachments checkbox.
  • To encrypt all outgoing messages: Select File > Options > Trust Center > Trust Center Settings > Email Security. Under Encrypted email, select the Encrypt contents and attachments for outgoing messages check box.

Things to Keep in Mind

There are a few things to keep in mind when using encrypted emails:

  • Sending and viewing encrypted email messages requires both sender and recipient to share their digital ID or public key certificate. This means you and the recipient each must send the other a digitally signed message, which enables you to add the other person's certificate to your Contacts. You can’t encrypt email messages without a digital ID.
  • If you send an encrypted message to a recipient whose email setup doesn’t support encryption, you have the option of sending the message in an unencrypted format.
  • This process also encrypts any attachments sent with encrypted messages.

Additional Email Security Tips

Here are some additional steps you can take to make sure your emails are secure from prying eyes:

Make Sure Automatic Windows Log-On is Not Enabled

Windows automatically logging in a particular user (i.e. you) when it starts up is convenient but it lets whoever restarts the computer get to your emails. Here's how to disable that behavior:

  1. Select Run... from the Start menu.

  2. Type "control userpasswords2" and press OK.

    Screenshot of the Run... window with "control userpasswords2" typed in
  3. Make sure Users must enter a username and password to use this computer is checked on the Users tab.

  4. Select OK.

Encrypt Your Mail Files and Folders

If you can't make files used by your email program private using the above methods, you can try protecting the folder your email program with a folder protection program. Here are a few to try:

Remember that emails that aren't encrypted before they're sent can be intercepted and read. Protecting files on your disk only prevent others from accessing the mail as it's kept in your email program.

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