offline primary keys [was: Re: Why 2.1 is delayed for so long]

[Robert J. Hansen]

> When you certify a subkey, you mean "I and only I have access to the 
> private component".

Not necessarily.  You're introducing policy.

> But yes, if OpenPGP does not formalise a meaning for certifications, 
> that is a design flaw, not a problem with my proposal per se.

Be careful: you might be wandering into a thicket here.

Some years ago David and I had a vehement argument over on PGP-Basics
over whether signatures were interchangeable.  The argument fizzled out
when we realized we were talking past each other: he was saying
(correctly) that *syntactically* signatures across different levels were
different and easy to distinguish, and I was saying (correctly) that
*semantically* OpenPGP ascribes little difference between signature
levels and thus in the absence of specific policy guidelines signatures
across different levels are interchangeable.  (A persona-level signature
is the same as a fully-vetted signature as far as what semantic meaning
OpenPGP ascribes to it goes.)

The moral of this story: Syntax and semantics are different.  OpenPGP
cares a lot about the former and almost nothing for the latter.

When you talk about "formalize a meaning", that sounds a lot to me like
semantics -- and the OpenPGP committee made a deliberate choice to avoid
semantics as far as possible.  The choice of what semantics should be
associated with what syntax in what contexts ... that's policy.