So, you've watched too many episodes of Spooks and are raring to get your data encrypted. After all, security is good. Yes? Certainly don't want those pesky Russians (or any nasty Anonymous hackers) getting hold of your secret secrets. How does it work on your Mac then? Lets see and have a run down of the pro's and cons of keeping your dirty laundry hidden away from prying eyes.
What is Encrytption?
Good first question. If you've asked this then back away from the encrypt button. Slowly and carefully. If however your "just askin'" then read on. Basically encryption takes your easy to read data and hides it away. This is done in a variety of ways but the basic idea is to run some kind of algorithm over the data that reduces it to gobbledygook unless the correct key is used to unlock it. These keys are basically impossible to guess or otherwise crack. This means only you or another person who knows they key can read your data. You use some forms of encryption already, probably without realising it, usually when you connect to secure banking web sites, payment pages on any reputable e-tailer and if your email is sent using SSL.
How can I get my Mac to go all MI5 on me then?
There are any number of available encryption applications, PGP, TruCrypt and Apple own FileVault amongst them. Some will encrypt individual files and folders while some offer whole disk encryption. Apple has recently introduced whole disk encryption into OS X Lion via File Vault 2 using its new Core Storage system, and more of this later. Each application works differently but all result in you data being locked away from prying eyes. In return they all make life a little less flexible. Security is all about he trade off. If you want absolute and total security the downside is an utmost unusable system, if you have no security at all then life is much simpler. Most people are somewhere along this axis but more towards the ease of use end.
So what are the advantages of encryption?
In a word security. Do it right and your data is safe. Should your Mac fall into the wrong hands (yes I know you just popped up to the counter at Starbucks for a refill and when you returned to your table your MacBook was, like, just gone man). If you are running whole disk encryption then all your Macs new owner is left with is the option to erase the hard drive. Yes they'll have your Mac, but not your bank log in details or those picture you were downloading from the internet for "research".
And the down side?
As stated before, ease of use always suffered under security. You'll have to remember to log in and log out and decrypt and rein crypt individual files. You'll also need to remember your secure encryption password. With all disk encryption, forget your password and your just as toast as the their who steals your Mac. Apple now offer the option to store your FileVault master password with them. Useful but a practise that will send shivers down the spine of any really security obsessed user. After all, what to stop "the Man" requesting this password from Apple. There's also an issue of speed. Encryption and decryption takes processing peer and this takes time. A Mac running whole disk encryption under Lion will be slower than one running without. Another issue, often forgotten comes should you grow tired of all this security. Disabling encryption can take a really long time. And uses large amounts of disk space. Turning off FileVault for example can easily run to a whole day or processing time AND required the same amount of free disk space and the total size of the encrypted data to decrypt to. Should you loose patience with this and simply elect to hose your hard drive with disk utility you will face on final obstacle. While you drive shows as empty the volume itself is still encrypted, but now with no decrypt key. The only way to get past this is the erase the entire disk (not the volume) using the erase option in Disk Utility, the usual reformatting won't work. What a pickle.
So is it worth it?
In normal use, probably not. Security comes at the price of ease of use, which is why you bought a Mac in the first place. If you do work on sensitive information then you should look at security, some professions (doctors etc) insist on it, but often, simply having a secure log in password, disabling automatic log in and using a password for your screensaver and sleep options may be enough. Encrypting individual folders is s good compromise and can work well. Full disk encryption should only be used if you really need security. Be aware however that your life will get harder, you will have to remember your passwords and you are still obliged to give them to border officials in some countries should they ask or your laptop could be destroyed (yes America I'm looking at YOU)!
In the meantime, remember, the Red Fox flies tonight. Pass it on.