MacOSX: FileVault

What is FileVault?

FileVault is a program built into MacOSX 10.3+ (Panther and Tiger). It secures your Home directory by encrypting its entire contents using the Advanced Encryption Standard with 128-bit keys. The program automatically encrypts and decrypts your files on the fly.

When you turn on FileVault, the operating system essentially turns your home directory into an encrypted disk image. When you log out, the disk image is unmounted, and all of your data becomes functionally invisible and irretrievable unless you have the password to remount the image.

Why Should I Use FileVault?

If you have a laptop, or are concerned about your desktop computer being stolen, FileVault provides excellent, military-grade data protection. Even if a thief has pulled your hard drive and mounted it in another computer, unless they also have your password, they cannot access the contents of your Home folder.

Things To Consider Before Using FileVault

FileVault interacts badly with VirusScan; people using both on their Macs have reported extreme system slowness.

Turning on FileVault requires about 1.5GB of free hard drive space; if you do not have sufficient space, you will not be able to use the feature.

FileVault uses your login password; should you forget that password, your data will be lost. As a safety feature to prevent such data loss, administrators can set a master password that can unlock any user account on the Macintosh.

Because FileVault's protection involves constant encryption and decryption, enabling it makes your system more sensitive and more likely to suffer file system damage from force-quitting applications and unexpected shutdowns (such as from power loss). You should back up your data regularly and might wish to use an uninterruptible power supply (UPS) to prevent data loss during power failures.

If you store data in a location other than your home directory, the contents will not be protected.

By the same token, only your Home directory is encrypted; other areas of your hard drive will be accessible if a thief mounts your hard drive on another computer.

FileVault does not (and is not intended to) protect your computer against hackers and viruses. You should make sure your firewall is turned on whenever your computer is connected to the Internet, and if you are concerned about Macintosh viruses (which at this point are fairly uncommon) you should install Virex or VirusScan, which are available at the OSU Site Licensed Software Downloads Page.

How Do I Turn It On?

1. Go to "System Preferences", then click on "Security".
2. If desired, click on "set Master Password" to set a master password.
3. Click on "Turn on FileVault" to turn on FileVault; select other options as desired.
4. When finished, close the FileVault window.