How to Password Protect Files and Folders With Encryption

Whether you want to store sensitive data on a USB drive, securely email it, or just add an additional layer of security on your hard drive, there are a variety of ways to protect your files with a password.

When we say we’re “password protecting” a file, we generally mean we’re encrypting the file so it can’t be decrypted and understood without your encryption password. That’s the most secure way to password protect files.

Create an Encrypted Archive

Windows XP allowed you to create password-protected ZIP files, but Windows 7 doesn’t. That’s fine — you can download a free third-party file compression program that will handle this for you. There are many file-compression programs you could use, but we recommend the completely free and open-source 7-Zip.

After installing 7-Zip, use it to create a new archive — either via the 7-Zip option in your Windows Explorer right-click menu or the Add button in the 7-Zip application. You’ll be able to specify a password for your archive — be sure you leave AES-256 selected as the encryption type. Any files and folders you add to your .zip file (or whatever other type of archive you choose to create) will be encrypted with your selected password. You’ll need to enter your password when you open your archive file in the future.

Encrypt an Office Document

Microsoft Office allows you to apply encryption to documents, securing them with a password. Microsoft switched to AES encryption in Office 2007, so if you’re using an earlier version of Office, the encryption will be nowhere near as secure.

To password protect a document in Office 2013 or Office 2010, click the File menu, click the Protect Document button in the Info section, and select Encrypt With Password. You’ll be prompted to enter a password, which you’ll have to provide each time you open the document in the future. You can also fully decrypt the document in the future, removing the need for a password.

Other productivity programs may offer similar features. For example, Adobe Acrobat allows you to create password-protected PDF files. Word 2013 can encrypt PDF files with a password, too.

Create Encrypted Volumes With TrueCrypt

TrueCrypt allows you to create encrypted volumes. TrueCrypt is a very flexible encryption solution, and you can use it in a variety of ways:

Create a small encrypted container stored in a file on your hard drive. You’ll need your encryption password to “mount” this file as a special drive, allowing you to view and manipulate its contents. When you “unmount” the drive, no one can see its contents without providing your encryption passphrase.
Use TrueCrypt to create an encrypted volume on a USB flash drive or other removable drive, allowing you to carry sensitive files around with you worrying that they could be viewed if you ever lose the drive. TrueCrypt can be used as a portable application, allowing you to access your encrypted data even on computers that don’t have TrueCrypt installed — the TrueCrypt program files can be stored on the external drive itself.
Encrypt your entire Windows system drive, forcing anyone to enter a password when booting your computer or resuming from hibernate. This ensures that no one can access the contents of your hard drive as long as you leave your computer locked or powered off. (Unless they use the freezer attack, which is uncommon in the real world.)