In light of TSA's reaction to the near-miss catastrophe on Northwest Flight 253 on Christmas Day, I'm glad to see that CNN republished an article by Bruce Schneier entitled, "Is Aviation security mostly for show?"
As important as laptop hard drive encryption is, it's not the silver bullet for protecting confidential data on laptops. Bruce Schneier described Joanna Rutkowska's "evil maid" attack against a disk encryption product. This type of attack would probably work against any disk encryption product because disk encryption does not defend against an attack where the attacker gets access to your encryption key.
As usual, risk management is about understanding the threat which you are trying to mitigate. Disk encryption does solve the stolen laptop problem. But if an attacker can get access to your laptop multiple times without your realizing it, the evil maid attack can defeat disk encryption.
PGP, a disk encryption vendor, discusses the limitations of disk encryption and as well as other defenses available to protect against evil maid and other attacks.
Bruce Schneier notes that two-factor authentication will defeat the evil maid attack. BTW, don't leave your token in the hotel room for the evil maid to find. 🙂
