On 07/11/2012 04:22 PM, Bob Friesenhahn wrote: > On Wed, 11 Jul 2012, Sašo Kiselkov wrote: >> the hash isn't used for security purposes. We only need something that's >> fast and has a good pseudo-random output distribution. That's why I >> looked toward Edon-R. Even though it might have security problems in >> itself, it's by far the fastest algorithm in the entire competition. > > If an algorithm is not 'secure' and zfs is not set to verify, doesn't > that mean that a knowledgeable user will be able to cause intentional > data corruption if deduplication is enabled? A user with very little > privilege might be able to cause intentional harm by writing the magic > data block before some other known block (which produces the same hash) > is written. This allows one block to substitute for another. > > It does seem that security is important because with a human element, > data is not necessarily random.
Theoretically yes, it is possible, but the practicality of such an attack is very much in doubt. In case this is a concern, however, one can always switch to a more secure hash function (e.g. Skein-512). Cheers, -- Saso _______________________________________________ zfs-discuss mailing list firstname.lastname@example.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss