Re: [PATCH] crypto: add key wrapping block chaining mode

[Stephan Mueller <smueller@chronox.de>]

Am Donnerstag, 23. April 2015, 09:46:09 schrieb Herbert Xu:

Hi Herbert,

> On Thu, Apr 23, 2015 at 03:39:11AM +0200, Stephan Mueller wrote:
> > The KW does not return an IV. The IV is used for encryption to stir the
> > encryption a bit. The resulting ciphertext now contains the mixed in IV.
> > For decryption, the IV is only used to verify that the one block in the
> > decryption operation matches the IV.
> > 
> > So, there is no IV returned by the encryption.
> 
> Of course there is.  The first 8 bytes of the ciphertext is the
> output IV.
> 
> If you really want to pedantic then make a function wrapper around
> the whole thing and copy the IV in there.

Ok, I am trying to get it moved to blkcipher.

I am still unsure how to handle the IV. The reason for that is the following:

Encrypt input: IV, plaintext

Encrypt output: processed IV, ciphertext

Decrypt input: processed IV, ciphertext, IV to use for compare operation

Decrypt output: plaintext

How do you propose I send 2 IVs to blkcipher?

-- 
Ciao
Stephan