[CRYPTO] cbc: Require block size to be a power of 2
All common block ciphers have a block size that's a power of 2. In fact,
all of our block ciphers obey this rule.
If we require this then CBC can be optimised to avoid an expensive divide
on in-place decryption.
I've also changed the saving of the first IV in the in-place decryption
case to the last IV because that lets us use walk->iv (which is already
aligned) for the xor operation where alignment is required.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
1 file changed