How to Open Encrypted Email in Outlook and Send it to Others?

A shocking number of cyberattacks point to emails as gateways for heinous crimes. According to reports of Gatefy, about 94% of the breaches involving malware occur through the use of email exchanges. The frightening statistics have led business owners to encrypt email messages when exchanging sensitive information about finances, identity, and business strategies. 

Quick Recovery – For Microsoft Outlook Mails

Encrypted email messages have significantly increased security among the business and greatly reduced information theft and hacking. More so, as more business transactions are done online, a great need for secured email exchanges arose these unprecedented times. The most widely used and trusted emailing software, Microsoft Outlook, is one of the leading emailing softwares available in the market. 

This article will discuss what encrypted emails are, how to encrypt messages, and how to open them securely using Microsoft Outlook.

What are Encrypted Emails?

Encrypted emails are types of emails that have contents of email messages disguised to prevent exposing, hacking, and stealing sensitive information from any unauthorized person or entity. The intended recipient can only read the encrypted email messages, which requires an authentication process and the like.

Outlook can support two encryption options:

  • S/MIME encryption (versions of Microsoft Outlook 2016 Outlook 2019) 
  • Microsoft 365 Message Encryption (Information Rights Management) for Office 365 Enterprise E3 license only.

How to Encrypt Emails in Outlook?

S/MIME Encryption Process

First, add a S/MIME certificate to the keychain on your computer. After, you will need to configure the signing certificate in Outlook.

Follow these procedures:

  1. Click the File menu, choose Options, then Trust Center and  Trust Center Settings.
  2. You will see in the left pane, Email Security, select it.
  3. Next, point to Certificate and Algorithms; under it, click S/MIME certificate.
  4. Select OK. 
  5. Lastly, Compose your message and then click Send.

Microsoft 365 Message Encryption Process

(Only Office 36 Enterprise E3 licensees have access to this functionality. Furthermore, the Encrypt-only option is only available to enterprise subscribers.)

Another process using Microsoft 365 encryption process can be done by following the steps:

  1. When writing an email message, select Options
  2. Under options, choose Encrypt and select the encryption functions you want to apply, such as Do Not Forward or Encrypt-only.

Outlook 2016 and Outlook 2016 Encryption Process

  1. When writing an email message, click on Options
  2. Select Permissions, then select the encryption option you want to apply on your email, such as “Encrypt-only.”

Encrypting One Message

  1. When composing an email message, select File, then Properties.
  2. Choose Security Settings and then tick Encrypt Message Contents and Attachments check box.
  3. Write your message, and click Send.

Encrypting All Outgoing Messages

Compose your email messages similar to any other emails when choosing to encrypt by default all outgoing messages. However, your receivers should have the digital identification to view or decode the email.

  1. Click on the File tab.
  2. On Options, Click Trust center, and then select Trust Center Settings.
  3. Then, select the Email Security tab under the Encrypted Email; tick on the Encrypt contents and attachments for outgoing messages.
  4. Additional settings can be done by selecting a specified certificate to use just by selecting Settings.

How to Open Encrypted Email in Outlook and Reply Message?

(The following process are done with Microsoft 365 Message Encryption)

There are two ways to open an encrypted message:

Option A: Using an OTP (One-time password)

Option B: Creating a new or using an existing Microsoft account

Option A: Opening an encrypted email using an OTP (One-time password) 

  1. First, click on the email message.html.
  2. Then choose to Use a one-time passcode. Selecting this will redirect you to a secure email portal of the sender.
  3. Expect to receive an email passcode from Open the email.
  4. The email will give you two numbers: a reference code that tells you the purpose of the email and the passcode.
  5. After receiving the passcode, return to the message.html and enter the code in the assigned entry field.
  6. Select continue to open the message. NOTE: Passcode expiry will be in 15 minutes
  7. You can now access the encrypted message.

Option B: Opening An Encrypted Email using a Microsoft account

  1. Select the encrypted message and open it. Choose Sign In.
  2. After opening the email, a message will pop up with the attached encrypted email that says Message encryption by Microsoft Office 365.  Open the File attached to it.
  3. To view the encrypted email, sign in.
  4. You have to create a Microsoft account if you do not have one, creating an account can be done on the same screen.
  5. Choose to Create A Microsoft Account For (referenced email address)
  6. Fill up all necessary submissions in the form and submit.
  7. Expect to receive a verification email. Open the message to verify your email address.
  8. After completing the verification process, navigate back to the inbox where message.html is located. Then, you will need to log in to your Microsoft account and see your encrypted email. NOTE: You will be signed out automatically when you’re idle for more than 15 minutes from the encryption portal.

Replying to an Encrypted Email

  1. When replying from an encrypted email, select reply or reply all.
  2. Write your reply and select send. Then, a copy of your encrypted message will also be sent to you.


The most significant offense against cyber attacks is the best defensive method we can apply in our business network. We can prevent big financial losses when we make sure that we are protected from dangerous tactics and schemes of evil individuals. Technological developments have come a long way to help us fight these hostilities and secure our business. 

Lastly, Microsoft never fails to amaze us by incorporating security features in all of their softwares. Users in the business industry have long trusted the brand’s products and have built the foundation of their digital business with Microsoft. Now that you have learned the process, it is time to apply it in your business!

Also, Read – Open OST file Without Outlook

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