At the very least, it is a safety issue, as all documentation and all relevant help given here says block size is 512 bytes. It is also a compatibility issue, as volumes done this way would only work on your specific system and could not be accessed and recovered anywhere else. My stance would be sure, shoot yourself in the foot, but do not call the result "LUKS". Regards, Arno On Wed, Apr 27, 2016 at 14:56:50 CEST, levent demir wrote: > Hi, > > I am a PhD student and works and I am working with cryptsetup and a hw > crypto engine. > > I am using an ATMEL board which is able to do AES-ECB mode for example. > > We have implemented an XTS version with all operations (XOR, GF > Multiplication, 2 AES : one for IV one for data...) > > My question is can we use the page size instead of the block size of 512 > bytes ? > > I have read some thread it is written that it could be a security issue > but I don't agree because : > > Now to implement XTS I do as follows basically : > > I take the IV encrypt it with the second part of the key, then I compute > the 32 tweaks values in -for example- an array tweak_buf[512]. > Then I just have to compute the XOR with plaintext. > I do a DMA encryption with ECB of the 512 bytes. > Again I xor the ciphered data with tweak_buf. > > Then I have ciphered a whole block of 512 bytes. > > Now my question, the hardware is supporting a DMA operation till 4096, > is it not interesting to encrypt 8 blocks at a time ? > It is exactly the same operation as encrypting each block > consecutively. > > Of course I need to pre-compute the 8 tweak_buf in a big > tweak_buf[4096].Then in only one DMA operation I will be able to encrypt > 4096 bytes with ECB mode. > > I hope you understand what I mean. > > Can you tell me if it is possible ? If yes can I use a previous patch, I > have seen that there are some works on it ? > > Thank you. > > > _______________________________________________ > dm-crypt mailing list > dm-crypt@xxxxxxxx > http://www.saout.de/mailman/listinfo/dm-crypt -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@xxxxxxxxxxx GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. -- Plato 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
