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Date:   Tue, 18 Aug 2020 23:51:28 +1000
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Eric Biggers <ebiggers@kernel.org>,
        Ben Greear <greearb@candelatech.com>
Subject: Re: [PATCH 0/5] crypto: Implement cmac based on cbc skcipher
Message-ID: <20200818135128.GA25652@gondor.apana.org.au>
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On Tue, Aug 18, 2020 at 10:31:39AM +0200, Ard Biesheuvel wrote:
>
> What do you mean? You cannot implement cbcmac using a cbc skcipher
> unless you provide a scratch buffer of arbitrary size as the
> destination, in order to capture the skcipher output IV as the MAC.

Please have a look at patch 6.  The trick is to use an SG list
chained to itself.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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