I think you nailed it: It's an unexamined assumption. But so, to me
at least, is the assertion that an author signature to a list is a
bad idea for senders and will only serve to confuse verifiers. I'd
like to see some data collected from such systems before I'm willing
to agree or disagree with either perspective. And until then, I
don't want to exclude anything.
I have to agree that more data could be helpful. You have mine, where
the retained signature isn't.
A favourite example of mine: A DKIM signature with an "l=" ...
Another: A DKIM signature arrived and validated, but failed to cover
the Subject: header field. ...
The DKIM spec certainly provides ample opportunity for signers to do
silly things. If we're doing a BCP, it might be useful to suggest
situations where a technically valid DKIM signature probably isn't
useful, with these two examples, l= that doesn't cover the whole
message and unsigned subject, being good examples.
R's,
John
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