local signatures: should they be importable by default in some cases?

[David Shaw]

On Jun 22, 2010, at 2:36 AM, Daniel Kahn Gillmor wrote:

>> Can you elaborate on the usage you're describing?
> 
> I'm thinking of a situation involving three people: Alice, Bob, and Charlie.
> 
> Alice has met Bob in person and has verified his key.  Alice does not
> want this information to be publicly available (e.g., she has concerns
> about exposing a transparent social graph via the keyservers).  However,
> Alice knows and trusts Charlie and wants to put Bob in touch with
> Charlie, even though Charlie and Bob have never spoken before, and
> certainly have not verified each others' keys.
> 
> Alice makes a non-exportable certification over Bob's key+userID, and
> mails it to Charlie (in an encrypted message, of course).  Charlie
> imports the certification.  Now even if Charlie does something like "gpg
> --send $BobsKeyID", the fact that Alice has met Bob will not be publicly
> exposed.

I'm not sure this is good behavior for Alice.  If she is concerned about whether her linkage to Bob is publicly known, why would she risk that by giving Charlie a signature (local or otherwise)?  Now she has not only to worry about keeping her linkage secret herself, but she also has to worry about Charlie keeping her linkage secret.

In the above scenario, it seems more reasonable for Charlie to locally sign Bob's key himself on Alice's say-so.

David