Messages in this thread | | | Date | Sat, 14 Oct 2000 15:21:09 +0000 | From | Ingo Rohloff <> | Subject | Re: A patch to loop.c for better cryption support |
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Reed Petty wrote: > Caution is advised when depending upon crypto systems that use relative > block numbers as IV. The security may not be a strong as hoped. > There are some who believe that "not unique" IVs (across multiple > filesystems) facilitates some methods of cryptanalysis. ... Ahh that explains it...
> Perhaps losetup can allow the user to specify a "IVseed" value > and then pass to the transfer modules IVseed + relative block. > This would also allow existing absolute block based encrypted file > systems to be relocated (IVseed = absolute # of 1st block), satisfy > those among us who demand unique IVs, and allow those who prefer > operational convenience at the cost of weaker security to do so. An IVseed is a good idea.
What would you think of using a secure hash function on the key as IVseed ? This should ensure almost unique IVs and you don't need a second parameter two encrypt/decrypt a file. (On the other hand this scheme is of course weaker than your approach...)
so long Ingo
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