[dm-devel] Re: [PATCH 3/3] dm-crypt: Add support for stream ciphers using blkcipher interface

[Herbert Xu]

On Thu, Nov 22, 2007 at 05:38:12AM +0800, Tan Swee Heng wrote:
> Current implementation of dm-crypt supports block ciphers of the form
> "template(cipher)", e.g. "cbc(aes)". It does not support stream
> ciphers of the form "cipher", e.g. "salsa20", that uses the blkcipher
> interface directly.
> 
> This patch adds support for stream ciphers using the blkcipher
> interface directly. It uses a special chainmode called "stream".
> Example of usage:
>     cryptsetup luksFormat -c salsa20-stream-plain /dev/loop0

I'd really like to have a new format altogether that does not
involve dashes as a separator.  The reason is that dash is used
as a part of the name of certain algorithms.

Once dm-crypt starts using the givcrypt interface instead of its
own IV generators, we can get away with just a single algorithm
string, of the form

	geniv(mode(block-cipher))

Obviously stream ciphers would just be

	geniv(stream-cipher)

So when that happens we can just use the format "-string" as
that's an invalid specification in the current format.

Of course we'd continue to support the current format as well
which can coexist with the new format forever.

Cheers,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert at gondor.apana.org.au>
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