On Wed, Feb 19, 2003 at 03:44:14PM +0000, David Woodhouse wrote: > On Wed, 2003-02-19 at 15:35, Erik Mouw wrote: > > File level encryption gives an attacker information about the files on > > your system. > > > > Suppose I can get hold of your disk and I want to know if you are > > subscribed to linux-kernel. I just mount the disk, and if I find a file > > called "dwmw2/Mail/linux-kernel", it gives me a large hint you are > > indeed subscribed. No, I can't decrypt the file, but that wasn't my > > purpose. I do however know the file metadata, like the filename, the > > owner, modification time, length, etc. > > Not if the metadata were encrypted too. But I still can see where the metadata lives on the disk, which gives me a hint what kind of filesystem you are using. The more information, the easier the attack. > You speak only of block-level encryption and of file-level (i.e. > application-based) encryption. But don't forget that there's a layer > _between_ the applications and the block device. :) > > My question was what's wrong with doing encryption in the file system? If you want to encrypt files, you have to do it right. Any information can lead to a possible compromise of the system, so the best is to hide everything, which can only be done by block level encryption. Erik -- J.A.K. (Erik) Mouw Email: J.A.K.Mouw@its.tudelft.nl mouw@nl.linux.org
Attachment:
pgp00324.pgp
Description: PGP signature
