From: Herbert Xu <herbert@gondor.apana.org.au>
To: "Stephan Müller" <smueller@chronox.de>
Cc: linux-crypto@vger.kernel.org
Subject: Re: [PATCH 00/13] crypto: copy AAD during encrypt for AEAD ciphers
Date: Thu, 12 Jan 2017 22:57:28 +0800 [thread overview]
Message-ID: <20170112145728.GA15595@gondor.apana.org.au> (raw)
In-Reply-To: <31581301.kpbcu3havF@positron.chronox.de>
On Thu, Jan 12, 2017 at 12:22:09PM +0100, Stephan Müller wrote:
>
> When addressing the issue in the algif_aead code, and expect that over time
> the AEAD implementations will gain the copy operation, eventually we will copy
> the AAD twice. Of course, this could be prevented, if the algif_aead code
> somehow uses the same SGL for the src and dst AAD.
Why would you copy it twice? You copy everything before you start
and then just do in-place crypto.
> > BTW, why are you only doing the copy for encryption?
>
> I was looking at the only AEAD implementation that does the copy operation:
> authenc. There, the copy operation is only performed for encryption. I was
> thinking a bit about why decryption was not covered. I think the answer is the
> following: for encryption, the AAD is definitely needed in the dst buffer as
> the dst buffer with the AAD must be sent to the recipient for decryption. The
> decryption and the associated authentication only works with the AAD. However,
> after decrypting, all the caller wants is the decrypted plaintext only. There
> is no further use of the AAD after the decryption step. Hence, copying the AAD
> to the dst buffer in the decryption step would not serve the caller.
That's just the current implementation. If we're going to make
this an API then we should do it for both directions.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2017-01-12 14:57 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-10 1:36 [PATCH 00/13] crypto: copy AAD during encrypt for AEAD ciphers Stephan Müller
2017-01-10 1:36 ` [PATCH 01/13] crypto: service function to copy AAD from src to dst Stephan Müller
2017-01-10 1:37 ` [PATCH 02/13] crypto: gcm_generic - copy AAD during encryption Stephan Müller
2017-01-10 1:37 ` [PATCH 03/13] crypto: ccm_generic " Stephan Müller
2017-01-10 1:37 ` [PATCH 04/13] crypto: rfc4106-gcm-aesni " Stephan Müller
2017-01-10 1:38 ` [PATCH 05/13] crypto: ccm-aes-ce " Stephan Müller
2017-01-10 1:38 ` [PATCH 06/13] crypto: talitos " Stephan Müller
2017-01-10 1:38 ` [PATCH 07/13] crypto: picoxcell " Stephan Müller
2017-01-10 1:39 ` [PATCH 08/13] crypto: ixp4xx " Stephan Müller
2017-01-10 1:39 ` [PATCH 09/13] crypto: atmel " Stephan Müller
2017-01-10 1:39 ` [PATCH 10/13] crypto: caam " Stephan Müller
2017-01-10 1:40 ` [PATCH 11/13] crypto: chelsio " Stephan Müller
2017-01-10 1:40 ` [PATCH 12/13] crypto: nx " Stephan Müller
2017-01-10 1:41 ` [PATCH 13/13] crypto: qat " Stephan Müller
2017-01-12 6:19 ` [PATCH 00/13] crypto: copy AAD during encrypt for AEAD ciphers Herbert Xu
2017-01-12 11:22 ` Stephan Müller
2017-01-12 14:57 ` Herbert Xu [this message]
2017-01-12 15:23 ` Stephan Müller
2017-01-12 15:27 ` Herbert Xu
2017-01-12 15:34 ` Stephan Müller
2017-01-12 15:39 ` Herbert Xu
2017-01-12 15:50 ` Stephan Müller
2017-01-12 15:53 ` Herbert Xu
2017-01-12 16:01 ` Stephan Müller
2017-01-12 16:06 ` Herbert Xu
2017-01-12 16:37 ` Stephan Müller
2017-01-13 10:23 ` Herbert Xu
2017-01-13 10:58 ` Stephan Müller
2017-01-13 11:04 ` Herbert Xu
2017-01-13 11:12 ` Stephan Müller
2017-01-13 11:14 ` Herbert Xu
2017-01-13 11:19 ` Stephan Müller
2017-01-13 11:26 ` Herbert Xu
2017-01-13 11:30 ` Stephan Müller
2017-01-13 11:33 ` Herbert Xu
2017-01-13 11:36 ` Stephan Müller
2017-01-13 11:39 ` Herbert Xu
2017-01-20 17:07 ` Cyrille Pitchen
2017-01-20 20:28 ` Stephan Müller
2017-01-23 13:10 ` Herbert Xu
2017-01-12 12:43 ` Stephan Müller
2017-01-18 14:57 ` Cyrille Pitchen
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