On Thu, Aug 17, 2017 at 11:46 PM, Kurt Andersen <ku...@drkurt.com> wrote:
> So I was able to retrace our design steps which led to the 3-piece model > (AAR + AMS + AS) and the reasoning for the AS, signing just the ARC header > sequence was to provide the verifiable chain of custody trace (though, of > course, only from participating intermediaries). Some of the recent tweaks > to the spec to deal with malformed sets of ARC header fields have weakened > that original idea. > > In keeping with Bron's general idea to simplify, I'd suggest that having > an AAR + [optional AMS] + AS would be a close approach for handling steps > which do not break the ingress signature. Skipping the AMS would be a sign > to downstream intermediaries that the prior DKIM or AMS was still valid > upon egress. (certain details would have to be worked out) > > Does that help the conversation? > No, I think this is a huge step in the wrong direction. Right now, we've got deployed code that we know works and improves the landscape. Everything else is - rightly or wrongly - conjecture. Let's keep the tech stable and move to experimentation. If anything, this is an excellent question for receivers - when evaluating AMS/AS, were there any situations where you required both signatures to truly validate a chain and make a delivery decision, or with the added ARC payload is now just having one sufficient? Seth
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