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by dredmorbius
20 hours ago
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I'd seen your earlier comment at the time. Your follow-up, here (<https://news.ycombinator.com/item?id=48938169>), was particularly insightful, and has influenced my thinking. Essentially: authentication / validation should happen out of band with phone number itself, for the reasons you've given. I do suspect that for routing authentication, header-level signifiers should be reasonably useful, but for strong identity or authority attestation, they're not. That's ... a deeper problem, but also one which can be solved independently. Oh, and I'd love to see that Dallas Morning News AT&T CEO interview story, if you could find it. Would this be it? "Watchdog Memo to AT&T's CEO: Didn't mean to get you in trouble", by Dave Lieber (July 8, 2016) <https://www.dallasnews.com/news/watchdog/2016/07/08/watchdog...> |
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AT&T took some bad press around that time, and in July 2016, the FCC, facing political pressure, and now sensing that the PR gods were now on their side, leaned on the major carriers to set up a 'task force' to get things moving. I remember sitting in the little room at the FCC while various telco industry grandees bloviated. We all agreed that ATIS and IETF should define technical standards since they'd already made a start (Jim M did ATIS, for example) and so everyone agreed that STIR/SHAKEN was going to be The Path.
The original STIR/SHAKEN assumptions were that the attestation would be carried throughout the network in a SIP header and that every SIP processing element would deal with it. Reality soon intruded in the form of ancient telco equipment that didn't have the headroom to process another bunch of bytes in every call setup message. Another idea was to have signing and verification done by SIP application servers, but that didn't pan out for the same reasons. (Forgive me, I'm going to toot my own horn here for a second:) I invented a scheme with my colleagues where the signing or verification was an HTTPS operation triggered by the SIP device at the network perimeter (a 'session border controller' in telco-speak) which made the problem more tractable. AT&T took my PowerPoint and submitted a stunningly close copy as their own to the FCC. I still have the slides somewhere. I was salty at the time but ah well, what can you do: my employer still made money off the product with other customers.