FileVault 2 security encryption - Mac OS X

FileVault 2 is the all new disk encryption method that comes with Lion, and it’s more secure than ever, using XTS-AES 128 encryption on your entire disk, as opposed to just the user directory as in past versions. The other huge change that came with FileVault 2 is the significant performance boost, where using full disk encryption barely makes a dent on system performance.

Bottom line: if you have a Core i3, Core i5, or Core i7 processor, you’ll barely notice the impact of disk encryption, regardless of whether you’re using an SSD or traditional platter drive. Is a tiny performance hit worth the peace of mind of total data security? You’ll have to decide, but if you have sensitive data and a newer CPU on your Mac, it probably is.

If you want to enable FileVault 2 yourself, you can do so in the “Security & Privacy” panel of System Preferences. You can even store the key with Apple which can be retrieved by answering some standard security questions, making it virtually impossible to accidentally lose access to your own data if you forget a password or lose the encryption key.

FileVault 2 Speed Test benchmarks