From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: "Stephan Müller" <smueller@chronox.de>,
"Herbert Xu" <herbert@gondor.apana.org.au>,
"David Miller" <davem@davemloft.net>,
"Ofir Drang" <Ofir.Drang@arm.com>,
"Yael Chemla" <Yael.Chemla@arm.com>,
"Linux Crypto Mailing List" <linux-crypto@vger.kernel.org>,
"Linux kernel mailing list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] crypto: mark cts(cbc(aes)) as FIPS allowed
Date: Mon, 5 Nov 2018 11:20:28 +0100 [thread overview]
Message-ID: <CAKv+Gu8x1LRKq4xJTrWfu7vQDPSzxYwEYGXG_o3Xv+Zsch9S-g@mail.gmail.com> (raw)
In-Reply-To: <CAOtvUMeRth4zrTZbEy6Co=+CR4==5oSDbaf760Yh4fj8UAf8bQ@mail.gmail.com>
On 5 November 2018 at 10:18, Gilad Ben-Yossef <gilad@benyossef.com> wrote:
> Hi Stephan,
>
> On Mon, Nov 5, 2018 at 10:50 AM Stephan Mueller <smueller@chronox.de> wrote:
>>
>> Am Sonntag, 4. November 2018, 11:05:24 CET schrieb Gilad Ben-Yossef:
>>
>> Hi Gilad,
>>
>> > As per Sp800-38A addendum from Oct 2010[1], cts(cbc(aes)) is
>> > allowed as a FIPS mode algorithm. Mark it as such.
>> >
>> > [1] https://csrc.nist.gov/publications/detail/sp/800-38a/addendum/final
>>
>> There are several types of CTS approaches. Only three of those are listed in
>> the SP800-38A addendum. The source code only refers to some RFCs.
>>
>> Did you check whether the CTS implementation matches one or more of the types
>> listed in the addendum? If yes, may I suggest to add a small statement in the
>> code noting this fact?
>
> Yes, AFAIK the software implements CBC-CS3 as described in the document.
> You have a very good point about this not document anywhere. I will
> send a patch.
>
I agree that it makes sense to document this.
> While we're at it, does someone find it useful if I implemented the
> other two modes?
> They are part of the standard as well, although I am not sure that in
> itself is sufficient cause.
>
Nope. The linux crypto API is not a general purpose cryptography
toolkit, it should only offer what we actually use in the kernel, or
we'll either end up with bitrot or with a disproportionate maintenance
burden for stuff nobody actually uses.
next prev parent reply other threads:[~2018-11-05 10:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-04 10:05 [PATCH] crypto: mark cts(cbc(aes)) as FIPS allowed Gilad Ben-Yossef
2018-11-05 8:50 ` Stephan Mueller
2018-11-05 9:18 ` Gilad Ben-Yossef
2018-11-05 10:20 ` Ard Biesheuvel [this message]
2018-11-05 10:30 ` Stephan Mueller
2018-11-09 9:54 ` Herbert Xu
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