| EcryptFS and Truecrypt are very different systems. Truecrypt is simulated hardware encryption. It creates a virtual encrypted hard disk, which your operating system can more or less treat like an ordinary hard disk, but for the kernel hooks Truecrypt adds to lock and unlock the disk. EcryptFS is an encrypted filesystem. Unlike Truecrypt, which encrypts individual disk blocks, systems like EcryptFS encrypt and decrypt whole files. All else being equal, you'd prefer an encrypted filesystem to a simulated encrypted hard disk. Some of the reasons are technical: the crypto involved in encrypting a block device is crappier than the crypto involved in protecting a file (most notably, block crypto is typically not authenticated). But at a higher level, the reason is that you'd like your cryptosystem to have as much information to work with as possible, and one nice bit of information for it to have is where files begin and end. All things are not equal though, and to select EcryptFS over Truecrypt, you also have to select EcryptFS's design and implementation over Truecrypt's. Truecrypt's design is simple and has been looked at more carefully than EcryptFS's. On the other hand, Truecrypt is an XTS cryptosystem, which isn't great. I would have a hard time making a recommendation between the two. It's more important that you understand the limitations of transparent disk encryption. Unless you are pretty regularly telling your crypto software that it's OK to unlock a given file or disk or whatever, then it's probably "always on", and your keys are always resident in memory, and your files are more or less always exposed to malware. Malware is a much scarier threat (for most people) than police raids. If you're interested: we work in a pretty high-risk environment (we handle a lot of hazmat). Our general crypto regime at Matasano is: * Everyone uses Filevault2's native XTS disk encryption (along with some fiddly rules for what state your machine needs to be in if it's in your bag). * Everyone uses OS X encrypted DMGs (I don't remember what the block crypto design for DMGs is, but you can check out John the Ripper if you're curious) to isolate different projects; we audit machines to make sure keys aren't in the keyring. * Everyone uses PGP for email and to encrypt specific files. If this sounds like a pain in the ass, be aware that this is pretty close to the minimum viable amount of security you can be providing a mobile device; if you're skipping one of these steps, you should know why. |
I disagree for these reasons:
1. This decreases composability. With encrypted filesystems, I can't mix and match filesystems and cryptosystems to suit my needs. There is no reason they need to be convolved.
2. This increases complexity. Now, the person writing the software has to be an expert in both filesystems and cryptosystems if they want to do a good job. There is more room for error. (You might say it violates the UNIX philosophy of "do one thing and do it well".)
3. This leaks information to an attacker. They know the layout of my files even without my password. I'm more comfortable with absolutely everything looking like a giant monolithic block of random data.