On Sun, Jul 25, 2010 at 03:14:24PM +0200, Christoph Anton Mitterer wrote: > On Sun, 2010-07-25 at 14:25 +0200, Milan Broz wrote: > > Just please note one thing, which is dm-crypt special here: > > > > default "plain IV" is 32 bit only, so if anyone uses it on >2TB partition > > some sectors shares IV (IV generator restarts, opening it to to watermarking > > and similar attacks). > > > > Please _always_ use plain64 (*aes-xts-plain64*) if you want use it for large > > devices. (plain64 produces the same IV for <2TB. > > Available since 2.6.33, Truecrypt 7 already does that, thanks:-) > > 1) What's the maximum size a partition can (securely) have with plain64? That would be larger than you can buy ;-) 512B * 2 ^64 = 9444 EB = 9.2 * 10^21 B > 2) Is plain64 solwer than the the normal plain? If not,... and even > if,.. wouldn't it be better to let "plain" be what currently "plain64" > is and to add a e.g. "plain32" or so, which people can use if the really > know what they're doing? I suspect backwards compatribility and not everybody running a kernel >= 2.6.33 > 3) In any case,.. this should go in the FAQ, Arno, can you add this > please? I will. Once I have seen an XTS spec ;-) Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@xxxxxxxxxxx GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
