[Feature Request] Multiple level subkey

[Andrew Gallagher]

> On 10 Sep 2017, at 16:28, Leo Gaspard <leo at gaspard.io> wrote:
> 
> I can think of at least one use case it covers in addition to an offline
> masterkey (but that would also be covered by C subkeys): the ability to
> sign others’ keys without using your masterkey. This would allow to not
> have to expose the keysigning device to untrusted data/software/hardware
> that would carry the to-be-signed key.

I think C subkeys are a *much* simpler solution for that use case. Better to treat this scenario as "solved in principle" and put it aside for the time being. 

A