[dm-crypt] What are the supported ciphers

Milan Broz gmazyland at gmail.com
Fri May 1 20:30:15 CEST 2015


On 05/01/2015 08:12 PM, Ralf Ramsauer wrote:
> Hi David,
> 
> you can use
> 
>     cat /proc/crypto
> 
> this is part of an example output:
> 
>     driver       : xts-aes-aesni
>     module       : kernel
>     priority     : 400
>     refcnt       : 4
>     selftest     : passed
>     type         : ablkcipher
>     async        : yes
>     blocksize    : 16
>     min keysize  : 32
>     max keysize  : 64
>     ivsize       : 16
>     geniv        : <default>
> 
> which means that this is the AES cipher driven in the XTS mode of operation. The keysize may be 32, 48 or 64 Byte. Last you need a initialisation vector generation algorithm (like ESSIV or Plain) which generates (at least) 16 Bytes.
> I remember this page http://code.google.com/p/cryptsetup/wiki/DMCrypt#IV_generators which is not accessible any more. I have in mind, that it contained a list of possible IVs.
> 
> Milan, Arno, is this page available at the new wiki? I couldn't find it.
> Besides that, maybe it is a good idea to list all possible combinations of cipher, mode and IV generator together with a 'recommendation' in the FAQ.

yes, it is here, links slightly changed because of markdown syntax:
https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt#iv-generators

FAQ is here
https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions

Some common combination you get when start "cryptsetup benchmark",
if kernel does not support some variant, you will see it.

Anyway, general advice: if you are not expert, do not experiment here and use default.
(to see default - run "cryptsetup --help")

Milan


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