Email remains the most valuable communication channel for businesses of all sizes and the most effective way to engage with your audience. Unfortunately, it is also an easy target for cybercriminals. Business Email Compromise earned hackers $2.4 billion in 2021. 

Since email is one of the least secure digital operations, companies don’t help themselves by leaving their folders unencrypted. On average, only 5% of business folders are properly protected. To make things worse, the mail transfer protocol (SMTP) is inherently unencrypted and delivers emails in plain text. This means attackers can intercept any unencrypted messages.

In this article, we’ll show you several ways to send documents via email securely. Let’s get straight into it!

Protect documents and files with a strong password

Nothing beats a strong password when a reliable password manager randomly generates it. Create a strong password and follow the steps below:

Microsoft Office documents

  1. Open your file.
  2. Navigate to File > Info > Protect Document (or Protect Workbook in Microsoft Excel and Protect Presentation in PowerPoint).
  3. Next, select the Encrypt with Password option.
  4. Enter your password.
  5. Confirm your password.
  6. Save the file.

Adobe Acrobat PDF documents

Please note that only the paid version allows you to edit a PDF file. Here’s how to protect PDFs in Adobe Acrobat Reader:

  1. Open your PDF.
  2. Select File
  3. Select Protect Using Password
  4. Select the Viewing or Editing option for recipients using the password.
  5. Enter your password and confirm it.
  6. Click Apply to save the file

Encrypt files on Mac

On Mac devices, all you have to do is use the default Preview application:

  1. Open your PDF with the Preview app
  2. Select File > Export
  3. Enter a file name.
  4. Select Encrypt.
  5. Enter your password and confirm it.
  6. Click Save.

Use End-to-End Email Encryption

End-to-End email encryption is a safer way to protect your text and files. It works by using a set of keys to encrypt the email before it is sent and decrypt the message upon receipt. Your exchanges are no longer readable but converted into scrambled cipher text instead. Two main end-to-end encryption protocols secure your email message and attachments. Here’s a quick overview of each of them:

S/MIME (Secure/Multipurpose Internet Mail Extensions)

The S/MIME protocol S/MIME relies on a centralized authority. It enhances email security by encrypting email messages and adding a digital signature. The encryption protects email contents against man-in-the-middle attacks, while the digital signature authenticates the sender’s identity and confirms that the sender actually sent the message. On top of that, S/MIME detects any alterations in the original message after it leaves the inbox. Almost all modern email clients support the S/MIME protocol.

PGP/MIME (Pretty Good Privacy/Multipurpose Internet Mail Extensions)

PGP/MIME relies on a decentralized authority. It’s special coding for the encryption and signing of e-mails by a hybrid cryptosystem. It allows you to create your own key code and is supported by Yahoo, AOL, and Android. PGP/MIME’s downside is the requirement of a third-party tool to use it.

How to secure documents and emails with S/MIME

Securing emails with S/MIME is pretty straightforward. All you need is an Email certificate issued by a trusted Certificate Authority. Email Certificates use PKI (public key infrastructure) to encrypt and decrypt messages. S/MIME is a bulletproof way to send documents via Email and is used on a large scale by businesses around the world.

You can order a personal or business S/MIME certificate from us. We also wrote a detailed guide on how to enable S’MIME encryption in outlook. To activate S/MIME for Gmail, follow the steps below:

Please note that the S/MIME feature is only available to Gmail Enterprise; Education Fundamentals, Standard, Teaching and Learning Upgrade, and Plus users.


  1. First, you need to enable hosted S/MIME for message encryption.
  2. Write your e-mail.
  3. Click on the lock icon located to the right near the recipient-related options.
  4. Select view details to change the S/MIME setting or select your preferred level of encryption:
    1. Green: The email is encrypted by S/MIME and requires decryption n via a private key before it can be read.
    2. Grey: The email is secured with TLS (Transport Layer Security). Note: For this option to work, both sender and recipient must use TLS to encrypt communications during correspondence.
    3. during transmission.
    4. Red: The email is not encrypted and will be sent in plain text.


To implement S/MIME encryption on iOS, follow the steps below:

  • Navigate to Advanced settings and enable the S/MIME option.
  • Change Encrypt by Default to yes.
  • Write your email.
  • Click on the lock icon near the recipient.
  • Attach your documents.
  • Send your email securely.

How to secure documents and emails with PGP/MIME

You need a third-party application to encrypt emails with PGP/MIME on Android devices. One of the most popular apps to do the job is OpenKeychain.  Download it from the app store and follow the setup instructions to encrypt, sned, and decrypt documents and emails.

If you want a quicker way to encrypt emails, an alternative option is to use a web email provider that offers end-to-end encryption. Some of the most reliable options are StartMail, Tutanota, and ProtonMail. Check them out!

Send your files securely via file-sharing services

The Internet abounds with file-sharing services that allow you to upload your files securely to third-party cloud servers. They’re handy when you need to send large files such as videos or high-quality photos. Apps like OneDrive, iCloud, SendAnywhere, and Dropbox streamline file-sharing by taking care of all security issues. All you have to do is set the file permission levels and then send the link via email or chat message to the intended recipient. 

Final Thoughts

We showed you the three most common methods to encrypt documents and emails. Password-protected documents and secure file-sharing services are better suited for personal exchanges. For business communication, S/MIME certificates are the best option. With S/MIME, you encrypt and digitally sign your emails and documents and create a foolproof transmission.

Regardless of what option you choose, don’t take email and file-sharing for granted. Without protection, you could be the next victim of a cybercrime. End-to-end encryption greatly reduces the risks associated with compromised documents and emails.

Phishing email vector created by katemangostar –