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Re: Diffs for next draft

2001-08-24 16:43:19

At 12:06 AM -0400 8/24/01, Michael Young wrote:

It seems that the most likely reason for a second "primary"
is that it has been updated.  If so, it seems that one should
defer to the most recent valid signature.  Can we say
that an implementation "SHOULD" do that, rather than leaving
it open?

As I remember it, when we introduced this, there were people who thought it
should be a MUST that there be exactly one of them. I thought this was a
bit fussy, myself -- as it requires the implementations to verify that
there's only one.

I came up with the present wording as a way to subtly admonish the practice
without presuming to know the answer. The simple and obvious way to deal
with the problem of multiple primaries is don't do that. This is the Henny
Youngman Solution (from the old joke: HY goes into the doctor and says,
"Doc, it hurts when I do this," waving an arm. The doctor replies, "Then
don't do that"). The penalty for writing multiple primaries is that the
receiver may do something perverse, and you can't use the standard as a
stick. Don't do that.

Secondarily, one way I look at it is as a receiver. I fetch a key from a
server and it has multiple primaries. How do I resolve this? Yeah, there's
been one recommendation in the last 24 hours since I started writing this
reply that it be the first one that counts. Why? Why the first? Why not the
last? I can make a convincing argument that it should be the last one, too.
But why the last. Why not the one with the latest date? I think I can argue
that the latest date is even more correct than either the first or the
last, unless of course it's in the future. Perhaps an even better answer is
to have the implementation ask the user which one to use.

This is my point: I don't see an obvious best answer. Furthermore, 2440 is
a data specification standard, not a user interface guide or software
construction manual. It tells implementers the things they have to do to be
compliant. What this really says that if you ever see a key with multiple
primary user names, then your guess is as good as mine, and I'm not going
to wag my finger at you for whatever rationale makes sense for you.