On Dec 15, 2021, at 17:09, Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> On Mon, Dec 13, 2021 at 04:51:59PM -0800, Chang S. Bae wrote:
>> == Disk Encryption Use Case ==
<snip>
>> $ cryptsetup luksFormat --cipher="capi:xts-aes-aeskl-plain" <device>
>
> plain64 is supposed to be used these days, not plain.
I see.
>> == Non Use Cases ==
>>
>> Bare metal disk encryption is the only use case intended by these patches.
>
> Since dm-crypt is the use case for these patches, you probably should CC this
> patchset to dm-devel@xxxxxxxxxx so that the dm-crypt developers are aware of it.
Oh, I should have included them. I was not aware of this mailing address.
Hi DM-crypt folks,
Here is the patch series:
https://lore.kernel.org/lkml/20211214005212.20588-1-chang.seok.bae@xxxxxxxxx/t/
I would appreciate if you give any feedback on this feature’s use case with yours.
>> +-----------+---------------+---------------+
>> | Cipher | Encryption | Decryption |
>> | (AES-KL) | (MiB/s) | (MiB/s) |
>> +-----------+---------------+---------------+
>> | AES-CBC | 505.3 | 2097.8 |
>> | AES-XTS | 1130 | 696.4 |
>> +-----------+-------------------------------+
>
> Why is AES-XTS decryption so much slower than AES-XTS encryption? They should
> be about the same.
Analyzing and understanding this with specific hardware implementation takes
time for us. Will come back and update you when we have anything to share here.
> Also, is the AES-CBC support really useful, given that for disk encryption,
> AES-XTS is recommended over AES-CBC these days?
Yes, we understand that AES-XTS is the primary option for disk encryption.
But it seems that AES-CBC had been used for disk encryption, [1]:
Comparing XTS to CBC for hard disk encryption
If a storage device vendor is seeking FIPS 140-2 certification today,
they will typically use CBC encryption, or even ECB. CBC is a good
mode, ...
As long as it is factual that the mode was once popular, it can help somebody
who wants to use Key Locker for an old disk image I think.
Thanks,
Chang
[1] https://csrc.nist.gov/CSRC/media/Projects/Block-Cipher-Techniques/documents/BCM/Comments/XTS/XTS_comments-Ball.pdf
