Generation ahead..Encrypted Hard-Disk

Self-encrypting hard drives are becoming a reality. One standard, led by the Trusted Computing Group, has been adopted by a number of vendors.The cost of encryption is virtually zero because the encryption itself takes place in hardware on the drive. This means that everything is encrypted by default, without compromising performance. We may remember to encrypt our most sensitive files, but at the same time forget to encrypt our email archive, previous versions of the sensitive file, and of course the swap and hibernate files which can contain everything. Encrypting everything by default protects us from these omissions.

How secure are these drives? Well, the encryption keys are generated and stored internally on the drive. Thus, the security of the system depends on the security of the key inside the drive. This means that the main question to ask encrypted-drive manufacturers is how is the key stored inside, and how secure is it? If a secure smartcard chip is used, and the key is password protected, then this is great. If the key is obfuscated and somehow hidden (of course, and still password protected), then someone stealing the drive can probably get to it given enough effort. However, you have still made their life difficult and they have to take the drive away with them (it’s unlikely that they’ll be able to do this without taking the drive apart). So, in any case, you have gained a lot. (I am ignoring the possibility of really bad implementations, although experience tells us that this can also happen not too infrequently…) It is worth noting that highly sensitive files should probably still be encrypted on a higher level (using an encryption key that is stored in a separate smartcard that you take with you). Keeping the encryption key in a completely separate place is always the best practice and prevents even the most concerted efforts to decrypt.

On a usability note, since the encryption keys are internal to the drive there is no key management issue. This is good because key management is often the biggest hurdle to adoption. Regarding data loss, it is important to realize that if the encryption key is somehow lost due to a fault in the drive, then this would be the same as if your hard drive was completely destroyed. So it’s important to also ask manufacturers what sort of fault tolerance has been built into the system regarding the encryption key.