✅How To Send a Secure Email In Outlook [ Step by Step Guide ]

When it comes to communication over the internet via mail service, the first thing now that comes to our mind is security. Security is a major concern when you are communicating with someone on the internet.

People usually use outlook email to transfer useful information, such as personal emails, financial data, sales reports, and project information with customers and employees.

That’s why mailboxes stored large amounts of sensitive information and if it is leaked it becomes a serious threat to your organization. But nowadays outlook provides end-to-end encryption, which is good for security purposes.

So today we will talk about how to send a secure email on outlook. The outlook is Microsoft’s product, which comes with the Microsoft office suite. The outlook comes up with some best functionality such as calendaring, contact managing, note-taking, ask to manage, and web browsing.

When you need to protect the privacy of an email, encrypt it. Encryption is a process in which the plain readable text is converted into scrambled ciphertext with a private key. Only the recipient of the email who has the private key can decrypt the message for reading. So, let’s start with how to send a secure email on outlook.


There are two methods to encrypt a message in outlook.

  1. S/MIME encryption: If the sender of mails and the recipient both have a mail application that supports the S/MIME standard. then you can use To use S/MIME encryption, and Outlook supports the S/MIME standard.
  2. Microsoft 365 Message Encryption: If the sender has Microsoft 365 Message Encryption, which comes up with Office 365 Enterprise E3 license. then you can use Microsoft 365 Message Encryption,


S/MIME stands for Secure/Multipurpose Internet Mail Extention. This technology allows you to encrypt your emails. S/MIME is based on asymmetric cryptography or public-key cryptography to protect your emails from unwanted access.

In this, you also get digitally signing features in your emails to verify you as the authentic sender and saves against many phishing attacks out there. This algorithm doesn’t rely on one key to both encrypt and decrypt. Each key performs a unique function.

Our Email Server Is Already Encrypted. Isn’t That Enough?

Absolutely it is best, but encrypting with Digital Certificates is also a smart move. This also prevents third parties software or outsiders from your email and intercepting sensitive data. However, it can not be limited to Digital Certificates encryption you also get server security with emails themselves.

Basically, your emails will be protected but some hackers can still get into your email system with some tools and can open your emails from there or access them while they cross through other servers. So definitely, your emails are well-protected on transit to your server.


With Office 365 Message Encryption, you and your organization able to send and receive encrypted emails between people inside and outside of your organization. The Office 365 Message Encryption works very reliably with Outlook.com, Yahoo!, or Gmail, and also with many other email service providers. Email message encryption helps recipients that only he can view the message content.


How does Office 365 Message Encryption work?

Office 365 Message Encryption is basically an online service that develops under the Azure RMS ( Microsoft Azure Rights Management ). That’s a part of Azure Information Protection. Were you got encryption of messages, identity, and authorization policies,

You can encrypt your messages by taking advantage of rights management templates, the Do Not have Forward option, and there is just an encrypt-only option.

Users can encrypt email messages and a variety of attachments by using these options.

As an administrator, you can also define mail flow rules for encryption. Office 365 Message Encryption provides various mail flow like you can create a rule that requires the encryption of all messages addressed to a specific recipient, or that contains the specific word in the content, and you can also specify that the recipient can’t copy or print the content of the message.

The new capabilities provide a unified sender experience whether you are sending your message inside the organization or to the recipients outside of Microsoft 365.

Before going to use Outlook S/MIME certificate encryption, you need to configure some settings to send a secure email.

Before starting any steps of the procedure, First, add a certificate to the keychain on your computer. After signing into your certificate just make a set up on your computer, then you’ll need to configure by these steps in Outlook.

  1. First, open your outlook software, under the File menu, go to options.
  2. After that, one new window will open. In the left pane of that window in the last, you will find, Trust Center, click on, Trust Center tab.
  3. In the same window, in Microsoft Office Trust Center, you will see an option, Trust center setting, click on that.
  4. Again a new window will open. In the left pane, you will see, Email Security select Email Security.
  5. Under the Encrypted e-mail, choose
  6. Under the Certificates and algorithm, Choose the S/MIME certificate
  7. Choose
  8. If you are an Office Insider with Microsoft 365 subscription, here’s what is new for you:
  • In an email message, choose
  • select Encrypt and pick Encrypt with the S/MIME option from the drop-down.
  • You will see an Encrypt with S/MIME if you have a S/MIME certificate installed on your computer.

For Outlook 2019 and Outlook 2016,

  1. In an email message in outlook 2016 and 2019, choose Options, and select Permissions.
  2. Write anything in your email after completing hit the, Send

Encrypt with Microsoft 365 Message Encryption

  1. In an email message, Choose
  2. Select
  3. Select an Encryption type, that has the restrictions you want to enforce like, Encrypt only or Do not forward.

For outlook 2019 and 2016

  • In an email message, select
  • Select
  • Select an Encryption type, that has the restrictions you want to enforce like, Encrypt only or Do not forward.

Encrypt a single message

  1. In a message that you are composing, click on
  2. In File, click on
  3. Click on Security settings.
  4. Select the Encrypt message contents and attachments check box.
  5. Compose your message and then

Encrypt all outgoing messages in Outlook

When you choose to encrypt all outgoing messages by default, you can write and send messages the same as with any other messages, but all potential recipients must have your digital ID to decode or view your messages.

  1. Click on the File
  2. In the left pane, choose
  3. A new window will open, choose, Trust center.
  4. In that, click on Trust center settings.
  5. Again a new window will open, inside that, in the left pane, you will see, Email security Click on that.
  6. Under Encrypted e-mail, checked Encrypt contents and attachments for outgoing messages.
  7. Choose Ok.

This was all about how to send a secure e-mail on outlook. With this setting, you will able to send your e-mail securely.

You May Also Read:-

How to Mark an email as Personal or Private or Confidential in Outlook – Office 365

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