On Thu, Jun 20, 2019 at 09:13:25AM +0800, Herbert Xu wrote: > On Wed, Jun 19, 2019 at 06:04:17PM -0700, Eric Biggers wrote: > > > > > +#define ESSIV_IV_SIZE sizeof(u64) // IV size of the outer algo > > > +#define MAX_INNER_IV_SIZE 16 // max IV size of inner algo > > > > Why does the outer algorithm declare a smaller IV size? Shouldn't it just be > > the same as the inner algorithm's? > > In general we allow outer algorithms to have distinct IV sizes > compared to the inner algorithm. For example, rfc4106 has a > different IV size compared to gcm. > > In this case, the outer IV size is the block number so that's > presumably why 64 bits is sufficient. Do you forsee a case where > we need 128-bit block numbers? Actually this reminds me, the essiv template needs to be able to handle multiple blocks/sectors, as otherwise this will still only be able to push a single block/sector to the hardware at a time. Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
