Secret-sharing for GPG?

[Roger Burton West]

Hi folks,

Two and a bit questions from a gpg newbie (though I've been using pgp
since 1993, and was very dissatisfied with pgp5, so gpg was excellent
news...) :

(1) Is there any interest in a secret-sharing encryption mode?  The 
principle is that one has a message key which is split into sections, 
such that any (N) of the sections are sufficient to recreate the key, 
but any (N-1) are not. While it's not the sort of thing one might often 
want to do, I can see it being useful for secret-key backups, among 
others. I am familiar with the mathematical protocols and have written 
implementations of this sort of thing before.

(1a) does this cause any problem in the context of the OpenPGP
standard?

(2) Is there any documentation on the calling of the MPI library? I've
mostly used libGMP before now.

Cheers,

Roger

-- 
Roger Burton West
Frontline Administrator, Demon Internet Ltd - of _course_ I don't speak
Home: roger at firedrake.demon.co.uk             for them!
Web: http://www.firedrake.demon.co.uk