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.

via How-To Geek http://www.howtogeek.com/170352/how-to-password-protect-files-and-folders-with-encryption/