How to encrypt emails in Microsoft 365

Egress | 9th Dec 2021

You can't be too cautious when protecting your business. If you frequently send sensitive information via email, it pays to protect that data. One good starting point is end-to-end encryption on your emails. This type of encryption stops malicious actors from intercepting your messages, protecting against potential data breaches.

Benefits of encrypting email 

There are several benefits of encrypting email in Microsoft 365 beyond simply protecting your data.

Comply with laws and regulations

Data protection acts such as GDPR state that the business is responsible for protecting the data of the people you work with. Some regulations specifically state that email encryption is required, while others state the business must take explicit steps to protect data — which, for most, means using encryption. This strategy protects the information within your business and helps you stay compliant.

Avoid security breaches

An unencrypted email could be intercepted by hackers, allowing them to steal data, passwords, and other sensitive information. Email encryption ensures only the intended recipient can open your email, helping protect against these kinds of attacks.

Authenticate emails

Hackers frequently try gaining access to sensitive data or systems by posing as trusted senders. Encryption services do more than protect the message; they allow users to verify that the sender is who they appear to be. This verification helps protect your business from phishing scams and other social engineering attacks.

How to encrypt email in Outlook

Outlook has several built-in encryption tools and the ability to install add-ons. The most common way for Outlook users to encrypt emails is through S/MIME. This type of encryption works if both the sender and recipient have Outlook and have installed their certificates. However, if a recipient doesn't use Outlook or another compatible service, the encryption won't work.

Another method is to use Microsoft 365's built-in message encryption. However, it's only available to Office 365 users. If both the sender and recipient use Outlook and an Office 365 subscription, the encryption works perfectly. The basic steps for encrypting an email in Outlook include:

  1. Open a new email message in Outlook
  2. Click File > Properties
  3. In the Properties section, click > Security Settings 
  4. Select the checkbox next to Encrypt message contents and attachments
  5. Compose your email message
  6. Click > Send

For other instances, such as emailing outside of the business where it's not possible to guarantee encryption using the tools above, an Outlook add-on could provide the answer. Egress Protect is a secure and simple-to-use solution, which adds additional encryption and authentication tools. It protects all your emails, not just those going to other Outlook users.

Benefits of an add-on solution 

While the built-in tools offer you some security, you can make your whole system more secure with an add-on. Here are some of the benefits.

Encrypt at rest and in transit

As well as message-level encryption, an add-on solution such as Egress Protect also encrypts your emails at rest. That means all your Outlook emails are safe from attack, not just those in transit. The built-in audit features also help with compliance, so you know your data protection efforts are in-line with industry standards. 

Flexible authentication

Authentication must be as straightforward as possible for users. That'll ensure all emails that need to be authenticated are. Flexible authentication techniques remove friction and support a recipient's requirements. That means all users can secure sensitive information, even when away from their computers and using their smartphones.

Reply securely

For those outside the business network, it needs to be easy to reply to an encrypted message. Once again, this removes friction and allows your business to operate as usual without requiring trusted partners to subscribe to an additional service.

Look for an easy-to-use, flexible add-on for encrypting Microsoft 365 emails. A tool such as Egress Protect ensures all employees can secure sensitive information without requiring recipients to use the same service.

When using Microsoft 365 and Outlook, you'll want peace of mind that your data is safe and that you're complying with relevant regulations. The built-in tools provide a good first level of defence but if you'd like to increase security and make compliance easier, look for an intelligent email security add-on such as Egress Protect to make email encryption an everyday part of your business.


Are Microsoft 365 emails encrypted?

Microsoft 365 has multiple encryption options available. The most popular is S/MIME, which requires the users to install and share a certificate. This type of encryption works well if both sender and recipient have the encryption tool set up properly. However, if one party doesn't have the right certificate, the email won't be encrypted.

Does Office 365 have end-to-end encryption?

According to a 2018 product announcement on the company's blog, Microsoft added a layer of protection for Outlook users that ensures end-to-end email encryption. 

How do I open an encrypted message in Outlook 365?

For the most part, Outlook does the hard work for you. If your account is set up correctly, opening an encrypted email is as simple as opening any other. Depending on the type of email encryption, you may have to enter a password in some cases. That feature will have been agreed upon with the sender ahead of the email hitting your inbox.