Clever exploit of DRAM to attack disk encryption

In your November article on laptop security, you mentioned the threat of having your laptop grabbed out of hands while you're typing on it. Combined with full-disk encryption, I use a very simple and effective defense against this: configure the system to immediately lock the screen on transitions from A/C power to battery. That way, the thief can't take your data any further than the length of the power cord.

It's not completely fool-proof, of course: as long as the encryption key is stored in RAM, it's theoretically possible to extract it, e.g., by transfering the DIMM to special hardware while keeping it powered. But I've never heard of anyone actually accomplishing this, and it's certainly beyond the ken of your average identity thief and possibly even the FBI.

I use Linux exclusively, and there implementing this is a simple matter of adding a hook into your acpid scripts. I'm not certain whether there's any easy way to do it in Windows or Mac.

One more thought in a similar vein: a lot of modern laptops include accelerometers so that they can make the hard drive protect itself if they detect that they're being dropped. I wonder if it would feasible to use these to detect that the laptop is being run-off-with.