How to Send an Encrypted Email in Outlook?

Email security isn't optional anymore - it's absolutely required. Outlook comes packed with powerful features like email encryption and Microsoft 365 protection. If you are looking to send a secure email in Outlook, then you're in the right spot. You can send secure emails and keep your sensitive info away from unauthorized access. In this blog, we’ll explain how to send an encrypted email in Outlook on any device to help you troubleshoot common issues and lay out best practices so your communications stay safe.

What is Email Encryption in Outlook?

When you encrypt your emails in Outlook, your message turns into a coded format or ciphertext, that only the intended recipient can decode with the right key. This means no one else can snoop on your message, keeping your sensitive information safe and secure.

How it Works

When you send an encrypted email from Outlook, the message is coded and secured in transit. The recipient can safely read the message by using the right key to unlock it.

• Scrambling (Encryption): When you send a protected email in Outlook, it replaces the plain text message with a coded version (ciphertext) using a key.
• Protection in Transit: The message remains unreadable as it travels through networks, ensuring its security against interception.
• Unscrambling (Decryption): The message is decrypted using the correct key by the recipient's device or a central server, and then converted back into readable plain text.

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Why Email Encryption is Important?

Sending an encrypted email in Outlook is key to protecting sensitive data in Outlook. It is a very useful feature for your privacy, security, reliability and meeting security standards.

1. Protects against Unauthorized Use

Encryption scrambles emails into a code that's pretty much impossible to read. Only the people with the right decryption key can access the information. This helps protect against hackers, third parties or even email providers while ensuring you can confidently send secure in Outlook.

2. Secures Sensitive Information

Using Outlook email encrypt features is especially important to protect your personal, financial and business info from being exposed. This way, you can steer clear of identity theft, financial scams and leaks of confidential stuff. It's important for anyone dealing with sensitive communication.

3. Ensures Regulatory Compliance

It helps you meet the legal, educational and industry-specific rules for protecting data. Plus, it helps you avoid fines and any legal trouble that might come from data breaches.

4. Defends Against Data Breaches

It serves as a key line of defense against both outside attacks and risks that might come from within. Even if someone tries to get in without permission, it helps keep data confidential.

5. Establishes Trust and Credibility

Encryption shows a real commitment to protecting the privacy of clients and everyone involved. By practicing secure communication with encrypted Outlook emails, you build a solid reputation and give a competitive advantage.

6. Guarantees Message Integrity

It makes sure that emails aren’t altered while they’re being sent or stored. It also supports digital signatures, which help verify who sent the message and ensure it’s authentic.

Types of Email Encryption in Outlook

Microsoft provides users with two main options that make it easy to send a secure email in Outlook and keep your data protected.

1. S/MIME Encryption (Secure/Multipurpose Internet Mail Extensions)
2. Microsoft 365 Message Encryption (OME)

1. S/MIME Encryption (Secure/Multipurpose Internet Mail Extensions)

S/MIME is one of the most secure Outlook email encrypt types. It works by using certificates to encrypt your messages and digitally sign them. Both the sender and the recipient need to exchange digital IDs for this to work. This way, only the intended recipient can open your encrypted email, keeping your messages private.

2. Microsoft 365 Message Encryption (OME)

OME is another commonly used email encryption in Outlook . It belongs to Microsoft 365 and enables you to choose options such as Encrypt Only or Do Not Forward.  One of the best things about OME is that you can send encrypted Outlook emails to any person, even when they are not using Outlook.

Key Difference Between S/MIME and OME S/MIME: 

• S/MIME: Certificate-based and best for organizations with strict security needs.  
• OME: Flexible, easy to use and ideal for sending secure emails to external recipients

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How to Send Encrypted Email in Outlook?

Sending an encrypted email in Outlook is simple and keeps your messages private. Whether on Windows, Mac, web, or mobile, Outlook provides built-in tools to easily send secure and protected emails. Just a few clicks and your email’s safe and sound. Learn how to make email secure in Outlook on different devices!

How to Send an Encrypted Email in Outlook on Windows

If you wanna keep your email private in Outlook, pop open the app, type what you wanna say, then hit up the Options tab and tap that encryption button. That’s it! Your message is safe and sound before you send it. Here’s how to send email securely in Outlook on Windows or Mac!

• Start a New Email: To send an Outlook email securely, Open Outlook app. Hit the New Email button to start a new message.

• Go to Option Tab: At the top, click on the Options tab in the new email window.

• Tap Encrypt Button: Look for the Encrypt button and tap it.
• Pick your Encryption Settings: Click Encrypt and a little menu will pop up. Choose from  the available options: 

Encrypt-Only: Locks up your message content and attachments.

Do Not Forward: Encrypts the message and the recipients can’t forward, copy, or print it.

• Write your Email: Type out whatever you need(work stuff, inside jokes ….)
• Send it Off: Click the Send button to send Outlook encrypted email.

How to Send Encrypted Email in Outlook on Mac

To send an encrypted email from Outlook for Mac, you need a Microsoft 365 license and must configure the encryption feature first. After setting it up, create a new email > go to the Options tab > click the Encrypt button and select a desired encryption level. Here how to do that:

1. Set Up Email Encryption (if you haven't already)

Obtain a Digital Certificate

You need a digital certificate installed in your Mac’s keychain. Without this, S/MIME encryption just won’t work.

Configure Outlook for S/MIME

Open Outlook and go to your account settings. Select your account. Set up your certificate for both signing and encrypting emails.

Verify Microsoft 365 License

Encryption features aren’t available to everyone by default. A specific license level, such as Office 365 Enterprise E3, is required. If you can’t access encryption, check your license, as highlighted by Lesley University.

Send an Encrypted Email

• Start a New Email:  To send a locked email in Outlook, Hit that New Email or New Message button. A new email window pops up. 

• Find the Options Tab: Check out the top menu and click Options tab. It’s hanging out up there with all the other icons.

• Get your Encrypt on: Look for the little padlock icon and click it.

• Choose Encryption Level: You’ll see a couple of choices:
• Encrypt-Only: Encrypts the email content but allows recipients to forward, print, or copy it. 
• Do Not Forward: Encrypts the email and prevents the recipient from forwarding, printing, or copying the content. 
• Finish and Send: Write your message. Add your recipient and hit Send.

How to Send Protected Email in Outlook Mobile App (iOS & Android)

You can follow the same steps for sending a secure email in Outlook Mobile App on both iOS (iPhone/iPad) and Android. To encrypt an email in Outlook, open a new email, tap "Options," select "Sign and Encrypt," and ensure a valid digital certificate is installed on your device and compatible with the recipient.

1. Before you Begin

Get Your Digital Certificate: Don’t skip this! You’ll need a real S/MIME digital ID from your organization's administrator. 
Turn on S/MIME in Outlook: Head to your Outlook account settings. Find the S/MIME toggle. Flip that switch ON and you’re good to go.

2. Steps to Encrypt an Individual Email 

• Start a New Email: To send Outlook encrypted email securely, open the Outlook app and tap to compose a new message.
• Access Message Options: Tap the three dots icon (•••) in the top-right corner.
• Choose to Sign and Encrypt: Click Sign and Encrypt from the list that pops up.
• Select your Encryption Option: Pick the S/MIME option that fits your needs.
• Send the Email: Write your encrypted email, send it off, and voilà - your emails are now safe from prying eyes!

How to Open and Read an Encrypted Email in Outlook

It's just as important to know how to open and read an encrypted email as it is to send an encrypted email from Outlook. Outlook makes it quite easy for both its users and others who don't use Outlook to securely access protected emails.

1. For Outlook Users

If you use Outlook (Windows, Mac, web, or mobile), encrypted messages open directly in your inbox. It's super easy.

• Look for the email marked “Encrypted” and Just click it. 
• Outlook automatically decrypts the message if you have permission.

2. For Non-Outlook Users (Gmail, Yahoo, Etc.)

Recipients without Outlook can still view the message:

• Open the email and tap the “Read the Message” link.
• Sign in with a one-time passcode or a Microsoft/Google account.
• After that, the email will pop up in a secure browser window, safe and sound.

3. How to Reply to Encrypted Emails

Replying works the same way:

• Hit “Reply” right inside the secure browser window or from your Outlook app.
• Your response gets sent out encrypted too, so your conversation stays private.

Troubleshooting Common Issues with Outlook Encrypted Emails

You may face some problems while opening or sending protected emails. Here are the most common issues and quick fixes. To troubleshoot Outlook encrypted email issues, check:

1. Is Your Internet Even Working?

• Make sure your Wi-Fi connection is stable..
• If the connection’s sketchy, Outlook’s not gonna play nice.

2. Can’t Find the “Read the Message” Link?

• Look for a link that says “Read the message” in the encrypted email.
• If it’s missing, the email might be messed up.
• Ask the sender to resend it.

3. Are Your Certificates in Order?

• Go to Outlook's Trust Center.
• Head to “Email Security” and check if your digital certificate is valid, actually installed and up to date. 
• If the certificate’s off, Outlook won’t let you in.
• Permissions like “Encrypt Only” or “Do Not Forward” have to be set up right

4. Try Safe Mode?

• Sometimes an add-in goes rogue.
• Try starting Outlook in Safe Mode (by typing outlook /safe in the search bar)
• If it works now, one of your add-ins is the troublemaker.

4. Don’t Forget the Spam Folder

• Attachments for decrypting the message can sometimes be flagged as spam. 
• Check there for any attachments or decryption files.

5. One-Time Passcode Expired?

• If you are using a passcode for decryption and it has expired.
• Just ask the sender for a new one.

6. Double-Check Your Account?

• Make sure you’re signed in with the email address the message was actually sent to.
• Sometimes it’s just a login thing.

7. Can’t Find the Encryption Option in Outlook?

• Your Outlook version might be old or your Microsoft plan doesn’t include it.
• Try updating Outlook or check with your IT person.

Most of these issues are just Outlook being extra. Check your basics first, ask for help if you need it and try turning it off and on again. 

Compatibility and Limitations of Outlook Encryption

Outlook email encrypt features offer some security but it has technical issues like compatibility issues with different versions and attachment size limitations. Key management is also risky, as Microsoft manages encryption keys and S/MIME can be easily read. Encryption only secures the content of messages and phishing and malware can still slip through, making it not foolproof.

Compatibility Issues

1. Classic vs. New Outlook

If you’re still using the classic Outlook desktop, you’ve got access to some old-school encryption features. But move to the “New” Outlook for Windows or Outlook Web App (OWA) and yep those options disappear. Microsoft basically left the good stuff behind in the classic version, making it harder to send an encrypted email Outlook without issues.

2. S/MIME & Purview

Microsoft Purview Message Encryption with IRM protection is not recommended for use with S/MIME-signed or encrypted messages in New Outlook and OWA.

Limitations

1. Subscription Required

Some encryption tools, like Microsoft Purview Message Encryption, want you to subscribe to Microsoft 365 before you can send a secure email Outlook.

2. S/MIME Hassles

Both the sender and the recipient need to get and handle their own S/MIME certificates from trusted providers.

3. Message Size

Purview-encrypted emails max out at 25 MB (attachments included). Trim that oversized file before you send an encrypted email in Outlook successfully.

4. Reliance on Microsoft for Data Security

In this setup, Microsoft controls your encryption keys, which means your data protection hinges on their infrastructure and policies - not yours.

5. IRM Limitations (Forwarding & Printing Controls)

While Microsoft Purview Message Encryption (or IRM) can restrict forwarding and printing, activating these controls typically isn’t straightforward. You’ll need extra Microsoft add-ons or have to configure specific policies, which adds complexity.

6. Phishing and Malware Exposure:

Encryption alone doesn’t defend against phishing or malware. Malicious emails can still arrive fully encrypted, which sometimes makes them harder for anti-malware solutions to detect or block.

7. Private Key Compromise Risks:

If a private encryption key is compromised, the entire security model collapses. All encrypted messages tied to that key become vulnerable, putting sensitive data at significant risk.

Best Practices for Sending a Secure Email in Outlook

Following best practices ensures that when you send secure email through Outlook, it’s not only private but also protected against misuse.

1. When to Use Encryption: Apply Outlook email encryption for any message containing financial data, business contracts and login credentials.
2. Sensitive personal information: Enhancing Security with Multi-Factor Authentication (MFA). Combine encrypted emails with MFA for increased protection. Even if account access is compromised, messages remain unreadable without secondary verification.
3. Preventing Phishing with Encrypted Emails: Always verify recipient addresses carefully before sending encrypted messages. Phishing attacks often exploit misdirected encrypted emails.
4. Ensuring Strong Passwords and Account Security: Create complex, unique Outlook passwords and regularly update them. Avoid reusing old or weak passwords.
5. Keeping Outlook and Microsoft 365 Updated: Install updates for Outlook and Microsoft 365 as soon as they’re available. Updates deliver the latest encryption enhancements and security patches.
6. Training Teams on Secure Communication: Provide staff training on proper encryption usage. Misuse can still lead to exposure, even with robust technology. 
7. Limit “Do Not Forward” When Needed: Use permissions wisely like” Do Not Forward” to stop recipients from sharing your email with others. Overuse can reduce effectiveness
8. Backing Up Important Encrypted Emails: Store backups of critical encrypted emails in secure locations. Ensures access if certificates or account details change

Alternatives to Outlook Email Encryption

If Outlook's built-in email encryption isn't enough, consider services like ProtonMail or Tutanota for end-to-end encrypted communication. Thunderbird with OpenPGP offers advanced encryption without changing your email address or provider or third-party encryption solutions like Virtru or Egress for robust protection.

1. Secure Email Service Providers

These providers offer end-to-end encryption and, in many cases, zero-access encryption. The goal is that only you (and your recipients) can read your mail.

• ProtonMail

ProtonMail offers end-to-end encryption and zero-access encryption for all your emails. Plus, it comes with some extra features like an integrated VPN and a password manager. All of its servers operate under strict privacy laws.

• Tuta

Tuta is built with open-source technology. It Offers end-to-end encryption for emails, calendars, subject lines and uses cryptography that's resistant to quantum attacks.

• Hushmail

Hushmail is a well-known provider that prioritizes privacy and has a strong reputation for delivering secure email services.

• Mailfence

Mailfence offers secure email along with built-in encryption and comes with extra features like an encrypted calendar and document storage.

2. Email Clients with Encryption (OpenPGP Support)

If you prefer to keep your existing email address but want to add encryption, these clients support OpenPGP - a widely recognized standard for secure email.

• <h4>Mozilla Thunderbird

Mozilla Thunderbird is a free and open-source email client. It has built-in OpenPGP integration - something that used to require the Enigmail add-on and it also supports strong encryption and digital signatures.

• Mailspring / K-9 Mail

Mailspring, which is cross-platform, offers a modern user interface and supports OpenPGP as well. On the other hand, K-9 Mail is a well-liked email client for Android that works with OpenKeychain for encryption.

3. Third-Party Encryption Solutions

For organizations using mainstream email platforms (like Microsoft 365 or Outlook), these add-ons and services can integrate advanced encryption and policy controls.

• Virtru

Virtru offers smooth encryption that fits right into your current email routines. It focuses on preventing data loss and gives you specific control over access. A lot of companies are already using it.

• Egress / Paubox / Proofpoint

Egress / Paubox / Proofpoint provide solid solutions with multiple layers of security, compliance tools, and top-notch encryption rules. They're crafted to safeguard sensitive communications, especially when you're dealing with larger volumes.