I’ve mentioned Whole Disk Encryption in the past. There are a number of products, both free and paid, which will allow you to encrypt your entire hard disk, or the hard disks on your servers.
In a recent study whole disk encryption (referred to as FDE in the study) has been shown to significantly hamper investigation. Basically, the encryption is too good. Even with techniques like cryogenic RAM freezing it’s often unlikely that the encryption can be bypassed.
But there’s a huge, gaping hole in such protection: you can’t USE encrypted data. For it to be accessible and usable, it has to be decrypted. (In other news, it is not possible to open properly locked doors, nor to pass through walls.)
And for the last few years, there has been a product out there which makes it possible to remove a computer without powering it down. This product is called HotPlug and it can be used, in conjunction with a portable power source, to remove a machine without disrupting its functioning. Be sure to watch the video.
Of course, lawful search and seizures aren’t the problem per se. But this does show that WDE isn’t a panacea. As with any security, it needs to be backed up by other defenses as well. Physical control trumps software security anyway. Which means, unremarkably, that even the newest technology doesn’t necessarily provide more security than a good padlock.