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Subject: Re: [PATCH v3 1/4] crypto: add eboiv as a crypto API template
To:     Gilad Ben-Yossef <gilad@benyossef.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com
Cc:     Ofir Drang <ofir.drang@arm.com>,
        Eric Biggers <ebiggers@kernel.org>,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20201029100546.28686-1-gilad@benyossef.com>
 <20201029100546.28686-2-gilad@benyossef.com>
From:   Milan Broz <gmazyland@gmail.com>
Message-ID: <3a4804a5-5d5c-1216-1503-c241cc24f3c2@gmail.com>
Date:   Fri, 30 Oct 2020 11:33:30 +0100
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On 29/10/2020 11:05, Gilad Ben-Yossef wrote:
>  
> +config CRYPTO_EBOIV
> +	tristate "EBOIV support for block encryption"
> +	default DM_CRYPT
> +	select CRYPTO_CBC
> +	help
> +	  Encrypted byte-offset initialization vector (EBOIV) is an IV
> +	  generation method that is used in some cases by dm-crypt for
> +	  supporting the BitLocker volume encryption used by Windows 8
> +	  and onwards as a backwards compatible version in lieu of XTS
> +	  support.
> +
> +	  It uses the block encryption key as the symmetric key for a
> +	  block encryption pass applied to the sector offset of the block.
> +	  Additional details can be found at
> +	  https://www.jedec.org/sites/default/files/docs/JESD223C.pdf

This page is not available. Are you sure this is the proper documentation?

I think the only description we used (for dm-crypt) was original Ferguson's Bitlocker doc:
https://download.microsoft.com/download/0/2/3/0238acaf-d3bf-4a6d-b3d6-0a0be4bbb36e/bitlockercipher200608.pdf

IIRC EBOIV was a shortcut I added to dm-crypt because we found no official terminology for this IV.
And after lunchtime, nobody invented anything better, so it stayed as it is now :-)

Milan