How To Replace FileVault With EncFS 65
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timothy
from the for-secretive-tweakers dept.
from the for-secretive-tweakers dept.
agoston.horvath writes "I've written a HOWTO on replacing Mac OS X's built-in encryption (FileVault) with the well-known FUSE-based EncFS. It worked well for me, and most importantly: it is a lot handier than what Apple has put together. This is especially useful if you are using a backup solution like Time Machine. Includes Whys, Why Nots, and step-by-step instructions."
Re:Question (Score:3, Interesting)
I like it because I have an office network and need business files to be encrypted, but accessible by other employees. File Vault is a single-user system unless your server is Mac OS X (ours is linux) and the files are stored in a user directory on that server. That opens up the problem that the login for the server then unlocks all the encrypted files.
Using Mac OS X disk utility, I've created several encrypted disk images on the server that users can mount over the network while having to give a password, etc. The server never knows anything about the encryption, etc It also enables a granular security policy to allow access to certain volumes to certain users.
Problems are that the disk images don't expand like File Vault apparently does. Also, doesn't use Time Machine effectively. (entire disk image would get backed up each time rather than only modified files). Other problem is that if the server becomes inaccessible, the client machines will write files to a temp location on the hard drive and the client user won't know they're not being saved to the encrypted disk image. Can present a security risk to those files being readable at a later date.
Seth
Re:Question (Score:5, Interesting)
Having read the article, I'd recommend that no one else did. It's written in a preachy patronising tone by someone who is clearly an idiot. For example, he complains about weak encryption because it's 'only AES-128 and you can't change that', except that since 10.5 it's been AES-128 or AES-256, even AES-128 is more than secure enough, and the vulnerability with FileVault comes from how they store the key, not from the encryption used.
He also mentions just as a throw-away 'Don't forget that encfs doesn't support fancy filesystem operations, so don't just throw your whole homedir in there - it won't work.' So, in fact, this can't replace FileVault. Looking at the EncFS web site, I can't see any evidence that it's been audited (even the design, let alone the code). He recommends storing your decryption key in the keychain, which seems very odd; if you don't trust Apple's encryption of your home directory, why would you trust Apple's encryption of your passwords?
He finishes with 'The biggest mistake Apple did with FileVault is storing the encrypted home directory on a virtual file system'. Given that the limitations of EncFS come from the fact that it isn't a proper filesystem, I'd have to disagree there. FileVault does encryption at the block layer, just like most other encrypted filesystems. If you bother to read any of the papers in this area, you will see that there are a number of good reasons for doing this.
Apple did two things wrong with FileVault. They didn't let Time Machine sync mounted File Vault images with other encrypted images and they didn't provide an implementation of something like the TRIM command to let the low-level bits delete space when it was no longer needed.