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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Sat, 12 Feb 2022 11:08:14 +0100
Message-ID: <CAMj1kXHtkxNkdpX46EmT94+ZkFyEkgXzZHOhpzb+DUu15r=7gQ@mail.gmail.com>
Subject: Re: [RFC PATCH v2 5/7] crypto: arm64/aes-xctr: Add accelerated
 implementation of XCTR
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Paul Crowley <paulcrowley@google.com>,
        Eric Biggers <ebiggers@kernel.org>,
        Sami Tolvanen <samitolvanen@google.com>
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On Fri, 11 Feb 2022 at 21:30, Nathan Huckleberry <nhuck@google.com> wrote:
>
> On Fri, Feb 11, 2022 at 5:48 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> >
> > On Fri, 11 Feb 2022 at 00:28, Nathan Huckleberry <nhuck@google.com> wrote:
> > >
> > > Add hardware accelerated version of XCTR for ARM64 CPUs with ARMv8
> > > Crypto Extension support.  This XCTR implementation is based on the CTR
> > > implementation in aes-modes.S.
> > >
> > > More information on XCTR can be found in
> > > the HCTR2 paper: Length-preserving encryption with HCTR2:
> > > https://eprint.iacr.org/2021/1441.pdf
> > >
> > > Signed-off-by: Nathan Huckleberry <nhuck@google.com>
> > > ---
> > >
> > > Changes since v1:
> > >  * Added STRIDE back to aes-glue.c
> > >
> >
> > NAK. Feel free to respond to my comments/questions against v1 if you
> > want to discuss this.
>
>  Oops, I misunderstood the tail block behavior of the CTR implementation and
>  thought it wouldn't work with XCTR mode.  I have XCTR mirroring the tail
>  behavior of CTR now. I'll submit it with the v3.

Yes, here's my version for reference:
https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/commit/?h=hctr2&id=5bb01649223080b7cde5740f441eb5e758ec357f