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MS Outlook: How to Secure Your Account & Encrypt Emails

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Read Time: 9 min
This post is part of a series called How to Use Microsoft Outlook (Essential Tutorial Guide).
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Picture it. Your customer places an online order. You email them a receipt. Even if the receipt doesn't include your customer's credit card information, it still likely contains a lot of personally identifiable information (PIN) such as your customer's name, address, telephone number, and email address. If your email were hacked, all the information would be leaked.

It seems nearly every day that a new data breach makes the news. We're constantly reading about how millions of us have had our data compromised. A study from the Identity Theft Resource Center shows that there have been 309 business-related data breaches affecting over 15 million people in 2018 alone.

It's no wonder that people are looking for ways to secure their outgoing email, including email from Microsoft email accounts. Email encryption is just one way to improve your Outlook security. In this article, we'll explore how to encrypt email in Outlook.

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Before going deeper into learning how to use encryption with your Microsoft email account, be sure to grab our Free eBook: The Ultimate Guide to Inbox Zero Mastery. It's packed with inbox organization strategies and killer tips for managing all your incoming email more efficiently.

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What Is Email Encryption & Why Is It Important?

Encryption is important for several reasons. First, lots of potentially sensitive information is shared through email. If an email is hacked into during the transmission process or even while it’s sitting in an email archive the hacker could potentially learn enough to steal account information. In a worst-case scenario, a hacker would also discover the password to your email account meaning not only could they access your messages at any time, they could also send (possibly malicious) messages using your email account. Your contacts may not realize that the messages didn’t come from you.

Encryption is a method of scrambling information so that it can’t be accessed by unknown third parties. If a message is encrypted only the intended reader who has a key to unlock the encryption will be able to view its contents. 

For a more in-depth look at email encryption review our series on email encryption.

MS Outlook provides you with some encryption options for individual messages. For these options Outlook uses digital IDs (also known as digital certificates) as a requirement for an extra layer of email encryption. You need a digital certificate to send an encrypted message. Your recipient also needs one to receive your encrypted message. The purpose of a digital certificate is to prove you are who you say you are.

Increasingly, many businesses are considering the use of encrypted email to communicate with their clients. This is particularly true for business in the healthcare or legal fields, where the likelihood of transmitting sensitive data is great.

Legal Issues Surrounding Email Encryption & Privacy Issues

Although email encryption is a relatively new area, there are already several laws that may impact its use. In general, laws such as the such as the EU’s General Data Protection Regulation (GDPR), the UK’s Data Protection Act (DPA), and similar laws were passed with the goal of protecting consumer data. In some cases, email encryption may be a way to help provide that protection. But, also be aware that in a few places some types of encryption are illegal.

Keeping your customer data secure is a good business practice. Email encryption could be just one piece of protecting your customer’s information if done in accordance with legal requirements.

Note: I’m not an attorney or a legal specialist and this article isn't legal advice. Also, the laws regarding data privacy are changing all the time. If you’ve got legal questions about using encryption for your business or about any other privacy issues, please consult with a lawyer who specializes in data privacy issues.

How to Encrypt Email in Outlook

MS Outlook has some information protection built in. However, in this tutorial we’re going to specifically discuss how to send an encrypted email through Outlook.

Outlook email does support email encryption for outgoing and received messages. To encrypt email in MS Outlook, you need to follow three basic steps:

  1. Get a digital certificate.
  2. Send and receive a message with the certificate.
  3. Use the Outlook encryption feature.

Let’s look at each part of the process more closely.

1. Get a Digital Certificate (Digital ID)

The first step in using MS Outlook for email encryption is to get a Digital ID, also known as a Digital Certificate. The safest way to do this is through an independent certificate authority (CA). A few certificate authorities that work with Outlook are:

Additional certificate authorities are available. Be sure to check a certificate authority’s reputation carefully before purchasing a digital certificate. The cost of obtaining a digital certificate varies, depending on the issuing agency.

Once you’ve obtained a digital certificate, you’ll need to install it. Follow the instructions provided by your certificate authority.

Note: The steps below may vary if you’re using an encryption plug-in for Outlook.

2. Send a Digitally Signed Message

Before you can send an encrypted message to a recipient, you and the recipient must exchange digitally signed messages. Unlike an ordinary email signature, a digital signature is connected to your digital ID and verifies that it’s really you sending the message.

1. To send a digitally signed message, first create a new message in Outlook. For information on how to compose a message in Outlook, review this tutorial:

2. From within the message, click the Options tab:

Options tabOptions tabOptions tab
Start with an open email message.

2. Click the More Options icon on the ribbon. The Properties box displays:

Properties boxProperties boxProperties box
Click Security Settings to access the dialog box to send a digitally signed message.

3. Click the Security Settings button on the Property dialog box. The Security Properties box appears:

Security Properties dialog boxSecurity Properties dialog boxSecurity Properties dialog box
Check the box next to Add digital signature to this message.

4. Check the Add digital signature to this message checkbox.

5. Make any other changes on the Securities Properties box, as needed.

6. When you’re done, click OK. Then click Close on the Properties dialog box.

7. Send your message with the digital signature to the recipient and request that they send a message with a digital signature back to you.

3. Encrypt a Single Message With MS Outlook

Once you and your recipient have exchanged digital signatures you can send encrypted messages to that recipient. Here's how to do it:

1. Start by creating the message you want to encrypt in Outlook. From within the message, click the File tab. The following screen appears: 

Click OptionsClick OptionsClick Options
Choose Options to access the Properties dialog box.

2. Click the Properties icon. The Properties dialog box appears over your message:

Properties dialog boxProperties dialog boxProperties dialog box
Click the Security Settings button.

3. Click the Security Settings button. In the Security Properties box, check the box next to Encrypt message contents and attachments.

Security properties dialog boxSecurity properties dialog boxSecurity properties dialog box
Click the check box to activate email encryption for the current message.

4. Make any other changes in the Security Properties box, as needed.

5. Click OK, then click Close on the Properties dialog box.

6. Send your encrypted message.

4. Encrypt All Outgoing Outlook Messages

You can also set your Microsoft email account to encrypt all outgoing Outlook email messages. However, keep in mind that recipients will need to have a key to open an encrypted message from you.

Still, if your messages always contain sensitive information and you generally send them to the same groups of people (such as your coworkers), you might want to consider using this setting to ensure that you don’t accidentally send out an unencrypted email with sensitive data.

Here’s how to set Outlook to encrypt all outgoing messages automatically:

1. From your open inbox, click the File tab. The Account Information screen displays:

Account Information screenAccount Information screenAccount Information screen
Select Options to open the Options dialog box.

2. On the Account Information screen, select Options. The Outlook Options dialog box appears:

Outlook Options dialog boxOutlook Options dialog boxOutlook Options dialog box
Select Trust Center to access the Trust Center dialog box.

3. From the panel on the left, select Trust Center and then select Trust Center Settings. The Trust Center dialog box appears:

Trust Center dialog boxTrust Center dialog boxTrust Center dialog box
Use the checkbox to encrypt all outgoing messages.

4. Click Email Security. Then check the box next to Encrypt contents and attachments for outgoing messages.

5. Click OK and then OK again.

By default, sent messages will now be encrypted.

5. What to Do When You Receive an Encrypted Message

What if you receive an encrypted message from a sender and you don’t have a key? You won’t be able to open the message until you verify your identity.

The appearance of your encrypted message may vary depending on what tool was used to encrypt it. Here's an example:

Encrypted Email Encrypted Using

Messages that were encrypted using will have a Read the Message button at the bottom. Here’s what an encrypted email message may look like when you receive it:  

Note: encryption is a premium feature available to Microsoft Office 365 users.

Encrypted email messageEncrypted email messageEncrypted email message
You can't see the body of an encrypted message without verifying your identity.

When you click the Read the message button, you’ll be given a screen with the choice to verify your identity through Google or with a one-time passcode

Verify your identityVerify your identityVerify your identity
Choose how you want to verify your identity.

Do one of the following:

1. Verify your identity using Google

1. To verify your identity using Google, click the Google button.

2. Sign in to your Google account at the prompt. 

3. Follow the instructions on the screen.

2. Verify your identity using a password

1. To verify your identity using a one-time passcode, click the Get a passcode button. Important: Don't close the window with the passcode prompt.

2. You’ll be sent a one-time password through email. (Careful, the password will only be valid for 15 minutes.) Enter the passcode at the prompt.

3. Follow the instructions on the screen.


You’ve just learned how to send a secure email in Outlook using email encryption. Email encryption is just one aspect of Outlook security. However, it can play a role in keeping your customer’s data more secure, which is an important part of doing business in today’s world. 

If you haven't already thought about ways to secure your customer's data and improve your Outlook security, it may be time to start thinking about it. Start by using the techniques listed above to make messages sent from your Microsoft email account more secure.

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