Messages in this thread | | | Date | Sat, 06 Mar 2004 20:14:42 -0800 | From | Mike Fedyk <> | Subject | DM for detecting bad disks was: dm-crypt, new IV and standards |
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Pavel Machek wrote: > Hi! > > >>>>Well, CTR mode is not recommended for encrypted file systems because it is very >>>>easy to corrupt single bits, bytes, blocks, etc without an integrity check. >>>>If we add a MAC, then any mode of operation except ECB can be used for >>>>encrypted file systems. >>> >>>what does "easy to corrupt" mean? i haven't really seen disks generate >>>bit errors ever. this MAC means you'll need to write integrity data for >>>every real write. that really doesn't seem worth it... >> >>The difference between "_1,000,000" and "_8,000,000" is 1 bit. If an >>attacker knew enough about the layout of the filesystem (modify times on blocks, >>etc) they could flip a single bit and change your _1Mil purchase order >>approved by your boss to a _8Mil order. > > > Hmm... long time ago I created crc loop device to catch > faulty disks. If cryptoloop can do that for me... very good!
Yes, a crc, or some other very low overhead DM target would be great for this. I haven't looked at DM too much. :( Does it already have something like this already? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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