Parameters/gcryctl to digest algorithms?

[Dmitry Eremin-Solenikov]

Hello,

I'm trying to extend GOST R 34.11-94 support in libgcrypt.
The problem is a selection of S-box to be used in compression function.
Currently algo is limited to the S-Box defined in the standard itself.

Initially I have hacked a version supporting CryptoPro S-Box (as required
by RFC4357) just by introducing another algorithm using that s-box.
However after looking at Ukrainian (DSTU) standards (order #114 dating
12.06.2007), I decided that it might be not so good idea. That order
defines several more s-boxes, with at least one of them used for
digest calculation. I can add another algo for that s-box, however I fear
that it would be an overkill. I was also thinking about reusing
flags part of md_open() call, but also couldn't come up with a good
enough solution.

What would be your thoughts?

-- 
With best wishes
Dmitry