Wondering how to send secure emails in Outlook?

Sometimes, we send confidential details and sensitive data via our Outlook mails that we would not want to reveal to unconcerned personnel. That is why putting some protection over those emails to keep them away from cybercriminals and hackers is essential. 

The essence of encrypting your outlook email is to stop unauthorized people from accessing the enclosed information.

Outlook email encryption changes the content of your email to an end to end encryption. That means only your enlisted recipients can access the details of the email. 

When secured, an outlook email opened by an unauthorized person will look like a scrambled ciphertext that makes no sense. The only way anyone can access such an encrypted message is by inputting a set private key. After the recipient enters a private key, the texts unscramble and become readable. 

If your outlook emails contain sensitive information, it is crucial to utilize email encryption to keep them inaccessible to cybercriminals. 

That way, even if your email were hacked, the encrypted messages will remain untampered with and unreadable.

Ready to start sending secured outlook emails? 

This article is a step-by-step guide to encrypting your outlook emails using three different methods. Here’s what we’ll cover: 

  • 3 Simple Methods To Encrypt Emails In Outlook 
  • How To Send Encrypted Emails In Outlook (S/Mime Certificate, Office 365 Message Encryption, And Online Addons)
  • How To Encrypt All Your Outgoing Messages At Once
  • How To Remove Encryption From Secured Outlook Emails 
  • Benefits Of Encrypting Your Outlook Emails

3 Simple Methods To Encrypt Emails In Outlook 

Microsoft Outlook emails can be encrypted using any of the three methods below;

  • Office 365 message encryption: This outlook email encryption method is only available to people with an office 365 email account. While the OME option allows you to send secure outlook mails to any email recipient, there is a condition for them to access the encrypted message. To make sure that recipients of the OME message can read it, the sender needs to pay for TLS connections. The receivers of the OME email may be unable to open the secured message if the TLS connection is not available, 
  • Certificate-based outlook Email Encryption(S/Mime): S/Mime means Secure/Multipurpose Internet Mail Extensions. It is an encryption technology that allows you to change your mails into an unreadable format. Unlike Office 365 message encryption, you cannot send S/Mime encrypted emails to free webmail users like; yahoo, Gmail, and iCloud. To use this kind of encryption, you and the recipients need to have an outlook account or any email application that allows S/Mime. You both need to have installed and shared encryption certificates for S/Mime to initialize. 
  • Outlook add-ons and extensions: There are various third-party outlook add-ins that you can use to send encrypted emails. Most of those third-party add-ins will allow you to send encrypted mail to any email client easily. While some add-ons are cheap, you can use others at zero cost. Though, make sure you choose a credible source to ensure the safety of your private data. Many free tools might not have the best security protection.

Below, we’ll cover each method on how to send secure and encrypted emails in Outlook in detail.

How To Send Encrypted Emails In Outlook (S/Mime Certificate, Office 365 Message Encryption, And Online Addons)

Using any of the three methods listed earlier, you can encrypt your outlook mails easily. 

All you need to do is ensure that any outlook mail encryption technique selected works for your purpose. 

When you have ascertained which Microsoft outlook encryption method suits your requirements, follow the steps below to initiate it.

Method 1: How to encrypt your Outlook email with S/Mime (Certificate)

Step 1: Add a certificate to the keychain on your desktop. 

  • Click on the link inserted in your pick mail to add a certificate. You can obtain a personal S/Mime or an Enterprise S/Mime.
  • You will be directed to a browser window where a password is required. Enter the password you used when obtaining your certificate.
  • Save the .p12 file on the screen and open it. 
  • Enter the same password used earlier to access the file.
  • The keychain access app will open automatically. If it doesn't, search for the keychain in your apps.
  • On the left side of the keychain menu, select Certificate under Category.
  • Click on the saved S/Mime.
  • If you obtained the certificate from a retailer, you need to add your S/Mime to a login chain.
  • After adding your keychain certificate to log in, the S/Mime becomes active.

Step 2: Link the S/Mime certificate to your Outlook profile

  • Open your Outlook account.
  • Click on Tools, then Accounts.
  • Select Advanced then, click on the Security tab.
  • Click on the newly imported certificate.
  • Open signed outgoing messages.
  • Select all three options on the screen.
  • Click on the Encryption certificate.
  • Confirm and leave the accounts menu.
  • Create a new email. You will see "the message will be digitally signed" in the message dialogue.
create a new email in outlook


  • Select Options under the File Menu.
  • Click on trust center then, Trust center settings.
In the outlook settings, open the Trust Center
  • Select email security.
  • Click on Encrypted email and choose settings.
  • Select Certificate and Algorithm, click Choose then S/Mime certificate.
After opening the Email Security tab, select the Certificates and Algorithms and select the S/Mime certificate
  • Confirm your options.
  • Create an email and send it. 
  • Your outgoing outlook mail should be digitally signed by now. 

Step 3: Exchanging Public Keys with a User to Exchange Encrypted Emails

  • When a signed email gets sent to contact for the first time, you will be asked if access should be allowed to the message. Click on allow to grant access.
  • If the recipient reverts to a S/Mime encrypted message, open the message.
  • Click the Details tab on the right side of your header.
  • Select Add Encryption Certificate to Contacts.
  • From there, you and the recipient can keep exchanging encrypted messages as long as your certificate remains valid.
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Method 2: How to encrypt Outlook email with Office 365 Message Encryption (OME)

Before using the OME, ensure that you are subscribed to:

  • Microsoft 365 personal or family.
  • Microsoft 365 Business premium. 
  • Microsoft 365 enterprise E3 or E5. 
  • or Office 365 A1, A3, or A5

Then follow the steps to send an encrypted email with office 365:

  • After composing the message you intend to encrypt, Select Options
Open the email options
  • Click on encrypt and choose the suitable encryption option. (Encrypt-Only, Do Not Forward, confidential or highly confidential)). Please note that only subscribers of Microsoft 365 that use Exchange Online can access the Encrypt-Only feature.
encrypt your messages one at a time with the Encrypt-Only feature
  • Send the message to the recipient(s)

If your recipient has an Outlook account, the message will open easily after Outlook verifies them. 

However, if your recipient uses another email application, they will see the email subject and a button to read it. The read button will direct your contact to Outlook online where the recipients are verified.

See the video guide on how to use email encryption in Microsoft 365 here for more info.

Method 3: How to encrypt Outlook emails with Outlook encryption add-ons

Outlook add-ons allow you to send encrypted emails to recipients of even free email clients without them doing any setup, signups, or installations

Here’s how to encrypt your outlook emails with third-party add-ons.

Install any third-party add-in of your choosing. Some popular options include Virtru, ProtonMail, Zix, and others.


  • Open your Outlook account.
  • Compose a new email.
create a new email in outlook
  • A Secure send button should be seen somewhere on the screen (probably at the left corner of your header)
  • If you don't see a Secure send button, Click on the message.
  • You should see the secure send button now.

On receiving the outlook add-in secured mail, your recipient will see only the subject and a button to access the message. 

After clicking the Access button, the mail recipient gets directed to a web page that shows the body of the message.

Now, here’s what to do if you want to encrypt all of your outgoing email messages in Outlook at once.

How To Encrypt All Your Outgoing Messages At Once

  • Drop the file tab and select options.
Open the email options
  • Click on trust center then, Trust center settings.
  • Click on Email security and select the correct option under Encrypted Email.
While in the Email Security tab, open the Encrypted Email settings
  • Note: For your recipients to open the S/Mime encrypted outlook emails, they must have your digital ID.

How To Remove Encryption From Secured Outlook Emails 

In case you are wondering if encryption can be removed from sent outlook emails, it is possible. Follow the steps below to remove the security from outlook messages;

  • Open the sent emails in your Outlook.
  • Click on any encrypted mail that you wish to decrypt.
  • Select file, click on encrypt, and then unrestricted access.

Here’s a video guide on how to decrypt your secured Outlook emails.

Benefits Of Encrypting Your Outlook Emails 

Why encrypt your Outlook email messages?

Outlook email encryption offers a host of perks to people who take the extra step to secure their email communications. 

Check out the various ways that email encryption benefits Outlook users and why it is non-negotiable for carriers of sensitive details below.

  • Email encryption ensures the protection of confidential details.
  • With the right encryption method, you can ensure that your mail is not intercepted and tampered with.
  • Encryption proves the credibility of authentic senders.
  • Outlook encrypted mails will only be accessed by your intended contact.
  • You can be assured of zero identity theft when an email is encrypted.
  • With the correct encryption option, you can nullify the possibility of replaying messages.


Now that you know how to encrypt your Outlook emails, it is crucial to select the most suitable option for effectiveness. 

If you are using S/Mime, protect your digital ID to avoid divulging it to unintended people. While the encryption will ensure that unauthorized access is disallowed, anyone with your digital ID can open your emails.

If you want a cheaper encryption option on outlook, use third-party add-ons. 

However, you will want to ensure that such a third-party app is verified and secured to prevent complications.

Finally, if you’re looking for more ways to manage and organize your email messages, be sure to also read:

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