ietf-openpgp
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Re: PoP & Signer's User ID subpacket?

2003-07-14 10:40:59

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"David Shaw" <dshaw(_at_)jabberwocky(_dot_)com> writes:
Do I strongly care about encrypt-only primaries in particular?  Not
really.  I do care about clean design, though, and adding a special
additional "no encrypt-only primaries" rule on top of the current
clean primary/subkey design seems without clear benefit.

I think that the rules are cleaner without encrypt-only standalone
keys: "Every key has a primary that can sign and any number of subkeys
(of any type)."  Just one rule, no special cases, nothing "on top".

I find it strange that you'd use the term "primary" for a top-level
encrypt-only key.  It can't have subkeys; there is no "secondary".

Can you explain what troubles you about encrypt-only primaries?

Aside from being an unclean exception to a simple model :-?

I think there is value in requiring uids to be self-signed.  To allow
encrypt-only top-level keys, one has to make a special case.  Given
that they are only very limitedly useful, I'd rather not have the
special case.

I recognize that requiring self-signatures on uids restricts some
otherwise valid uses, and that it doesn't provide any additional
security given a strong trust model and a proper understanding of its
limitations.  I still think it's worthwhile.  [Note that the same is
true of the signing-subkey problem.  I acknowledge that the problem
was more serious there, and the uses of non-owned subkeys are more
limited.  (By the way, I like David's signature-in-a-subpacket
solution.)  The same is also true of the requirement that a key have
at least one uid.]

Hal observed that all *existing* encrypt-only algorithms really can
support signing anyway.  Who knows whether that will hold up over time?
If we're convinced that it will, I'd rather remove the encrypt-only
notion from the algorithm entirely (putting it in the key preferences
instead).

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