From: Milan Broz <gmazyland@gmail.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@vger.kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
Eric Biggers <ebiggers@google.com>,
device-mapper development <dm-devel@redhat.com>,
linux-fscrypt@vger.kernel.org,
Gilad Ben-Yossef <gilad@benyossef.com>
Subject: Re: [PATCH v9 3/7] md: dm-crypt: switch to ESSIV crypto API template
Date: Mon, 12 Aug 2019 09:44:47 +0200 [thread overview]
Message-ID: <82a87cae-8eb7-828c-35c3-fb39a9abe692@gmail.com> (raw)
In-Reply-To: <CAKv+Gu-ZPPR5xQSR6T4o+8yJvsHY2a3xXZ5zsM_aGS3frVChgQ@mail.gmail.com>
On 12/08/2019 08:54, Ard Biesheuvel wrote:
> On Mon, 12 Aug 2019 at 09:33, Milan Broz <gmazyland@gmail.com> wrote:
>> Try for example
>> # cryptsetup luksFormat /dev/sdc -c aes-cbc-essiv:sha256 --integrity hmac-sha256 -q -i1
>>
>> It should produce Crypto API string
>> authenc(hmac(sha256),essiv(cbc(aes),sha256))
>> while it produces
>> essiv(authenc(hmac(sha256),cbc(aes)),sha256)
>> (and fails).
>>
>
> No. I don't know why it fails, but the latter is actually the correct
> string. The essiv template is instantiated either as a skcipher or as
> an aead, and it encapsulates the entire transformation. (This is
> necessary considering that the IV is passed via the AAD and so the
> ESSIV handling needs to touch that as well)
Hm. Constructing these strings seems to be more confusing than dmcrypt mode combinations :-)
But you are right, I actually tried the former string (authenc(hmac(sha256),essiv(cbc(aes),sha256)))
and it worked, but I guess the authenticated IV (AAD) was actually the input to IV (plain sector number)
not the output of ESSIV? Do I understand it correctly now?
Milan
next prev parent reply other threads:[~2019-08-12 7:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-10 9:40 [PATCH v9 0/7] crypto: switch to crypto API for ESSIV generation Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 1/7] crypto: essiv - create wrapper template " Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 2/7] fs: crypto: invoke crypto API for ESSIV handling Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 3/7] md: dm-crypt: switch to ESSIV crypto API template Ard Biesheuvel
2019-08-12 6:33 ` Milan Broz
2019-08-12 6:54 ` Ard Biesheuvel
2019-08-12 7:44 ` Milan Broz [this message]
2019-08-12 7:50 ` Ard Biesheuvel
2019-08-12 13:51 ` Milan Broz
2019-08-12 14:19 ` Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 4/7] crypto: essiv - add tests for essiv in cbc(aes)+sha256 mode Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 5/7] crypto: arm64/aes-cts-cbc - factor out CBC en/decryption of a walk Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 6/7] crypto: arm64/aes - implement accelerated ESSIV/CBC mode Ard Biesheuvel
2019-08-10 9:40 ` [PATCH v9 7/7] md: dm-crypt: omit parsing of the encapsulated cipher Ard Biesheuvel
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