On Tue, Jul 13, 2004 at 01:07:02AM +0200, a.engels@xxxxxxx wrote: > > Nice, I havent thought of this possibility. Maybe one could store a md5 > > checksum of the crypto container inside the crypto container itself and > > check consistency when the fs is mounted. However, this would mean to read > > the entire crypto container at each mount. Adding checksums to each block > > (checksum also includes position of block) would be another way. > > I need to correct myself: if the last method is used, its not possible to > move blocks inside the crypto container, however an elder version of this > block could be used to overwrite the new one without notice. A combination of the two methods might be of some use though. You can checksum each block, and then checksum the checksums (will speed up checksum verification of the whole filesystem by some [large] factor). You may not notice a modified block at mount if an attacker preserves its checksum, but if you verify each block's checksum before reading and maybe writing (caching, of course) you should not be tricked into using a modified block. Thougt, -- Pav http://www.againsttcpa.com/ ,., My type: Dvorak. http://swpat.ffii.org/ ,``:'', {o ! o} Gain your human right of ] -+- [ My GPG/PGP key is now available at privacy: use cryptography! \ ! / x-hkp://search.keyserver.net:11371. `-' `shell$ gpg --keyserver x-hkp://search.keyserver.net:11371 --recv-key 164C028F` - Linux-crypto: cryptography in and on the Linux system Archive: http://mail.nl.linux.org/linux-crypto/
