File Encryption

How to Encrypt Files for Secure Email Transmission or Storage

Why Encrypt?

Massachusetts Law requires that legally-protected personal financial information be encrypted if sent over public networks, such as the internet. You may also need to protect information your office considers confidential, regardless of any legal requirement. This document describes ways to encrypt files prior to sending them via e-mail or storing them.

What is Encryption?

Encryption protects the contents of a file from being read by anyone who doesn’t have the encryption key. When encrypting a document or file, you will usually need to supply an encryption key in the form of a password or passphrase, which is then used to transform the document’s contents in such a way as to make the document unreadable. The encrypted document will need to have the password entered before it can be opened.

Important: Once a document has been encrypted, you can not open it without the password. Consider that it may be years before the file is needed, and if the password is forgotten, the file is worthless. Don’t rely on your memory. Make sure that passwords are stored some place safe before encrypting important information and make sure the passwords (or the location of the passwords) are made available to the appropriate faculty or staff.

Important: If you encrypt a file, attach it to an email message and send it to the recipient, do not send the password via email, either in the same or a separate message. Instead, send the password using another means of communication, such as a phone call or text message.

What can be Encrypted?

Fortunately nearly all devices and files can be password protected.  Windows and Mac laptops can be protected with BitLocker and FileVault.  Portable flas drives, or external hard drives can be secured with those programs as well.  Word, Excel and PDFs can be password protected.  Or a collection of files can be “zipped” for secure transfer.

Portable devices like iPhones and tablets can (and always should!) be protected with a passcode.

How Do I Encrypt a Document?

A number of widely-used software applications can encrypt documents, including Microsoft Office Word, Excel, and PowerPoint, Acrobat DC.

Microsoft Office Documents

For directions see:

Adobe Acrobat Professional (PDF)

For directions see:

General-Purpose Encryption Tools for Windows

7-Zip is a free Windows program which can compress files to save space when storing them or transmitting them across a network. 7-Zip creates a compressed archive file which can contain one or many files. The archive file can be encrypted and then securely sent as an attachment via e-mail. 7-Zip works with any kind of file (Word, Excel, PowerPoint, PDF, JPG, etc).

For more information See:

General-Purpose Encryption Tools for macOS

macOS comes with a program named Disk Utility, which can be found in Applications > Utilities. You can use Disk Utility to create an encrypted disk image, which can hold one or more files or folders. Once created, the Disk Image is stored as a file, copied to another disk or sent via e-mail as an attachment to another Mac user.

For directions See (scroll down to ‘Create a secure disk image’):