Email encryption and added security to files sent through email

Overview

All Office 365 emails, whether sent via the Outlook web client or Outlook desktop client, are encrypted by default using Transport Layer Security (TLS). This encryption ensures that emails remain secure from the moment they are sent until they are received by the intended recipient. This does not protect the content of the email, however, once it reaches the recipient.

Additional Email/File Encryption for Enhanced Security

For added security, users can encrypt files before attaching them to an email, and they can also encrypt the email itself. This provides an extra layer of protection, particularly for sensitive information. However, since the recipient needs a password to decrypt the files, it is recommended to follow these best practices:

1. Use a Strong Encryption Tool:

   • 7-Zip is recommended for encrypting files.

   • When compressing a file, choose the option to add a password for decryption.

2. Send the Password Separately:

   • Send two separate emails:

     • The first email should inform the recipient that an encrypted email will be sent with the file, and that both will be password protected.

     • The second email should be encrypted, and should contain the encrypted file, along with the password needed to open it (See the KB Article: How to Encrypt an Email Message to Protect Sensitive Data).

By following these steps, you ensure that even if an email is intercepted, the file remains secure and accessible only to the intended recipient.