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

[Stephan Mueller <smueller@chronox.de>]

Am Mittwoch, 22. April 2015, 14:13:54 schrieb Herbert Xu:

Hi Herbert,

> On Wed, Apr 22, 2015 at 01:53:24PM +0800, Herbert Xu wrote:
> > On Wed, Apr 22, 2015 at 06:36:59AM +0200, Stephan Mueller wrote:
> > > The key wrapping is an authenticated encryption operation without
> > > associated data. Therefore, setting of AAD is permissible, but that data
> > > is not used by the cipher implementation.
> > 
> > In that case you should return an error if AAD is provided rather
> > than silently discarding them since by definition AEAD must include
> > the AAD in the integrity value.
> 
> In fact drop the AEAD altogether and just use ablkcipher.  The
> integrity value is then simply the output IV.

Initially I was playing with ablkcipher. But then I moved to AEAD because the 
ciphertext is longer than the plaintext.

Isn't it a basic assumption to ablkcipher is that the ciphertext is equal in 
size as the plaintext?

-- 
Ciao
Stephan