Hi, On Sat, Jan 15, 2011 at 02:00:02PM +0100, Nikos Mavrogiannopoulos wrote: > On 01/06/2011 07:16 PM, Phil Sutter wrote: > > When trying to en-/decrypt a buffer using CBC in two steps by > > passing a part from the buffer's start at first, and then the > > remaining data in the second call, the second operation depends on > > the first one in that it's IV depends on it's result. Insiders know > > of course, that the IV of any CBC block to operate on is simply the > > enciphered last block. So this patch is maybe most useful for > > everyone else, altering the passed IV upon returning the results. > > Why do you need that? This is really CBC specific and might make no > sense in other modes (that might be added in the future). If the code > this flag is supposed to target is CBC-specific anyway, wouldn't it be > easier to just use the last block?
Well, isn't the whole IV-concept kind of CBC-specific? Of course, if the continuative IV is _always_ the last block (whose size also may vary from one cipher to the other), one could easily use that. But I suppose, this is subject to change (not really, but there will probably be algorithms which use the IV differently). After all, this is basically just the cryptoapi's behaviour exposed. So there is no calculation done in cryptodev at all, just the updated cdata->async.iv written back to userspace. Greetings, Phil -- Viprinet GmbH Mainzer Str. 43 55411 Bingen am Rhein Germany Zentrale: +49-6721-49030-0 Durchwahl: +49-6721-49030-134 Fax: +49-6721-49030-209 phil.sut...@viprinet.com http://www.viprinet.com Sitz der Gesellschaft: Bingen am Rhein Handelsregister: Amtsgericht Mainz HRB40380 Geschäftsführer: Simon Kissel _______________________________________________ Cryptodev-linux-devel mailing list Cryptodev-linux-devel@gna.org https://mail.gna.org/listinfo/cryptodev-linux-devel
