This doesn't seem any more open than Verified by Twilio.

Why would you trust Verizon/Comcast more than Twilio?

As not a customer of both, STIR/SHAKEN doesn't help me.

1. The promise being made is different. SHAKEN/STIR doesn't promise to only let through legitimate calls, it only promises to make caller ID accurate to prevent spoofing. This allows the weight of existing laws against robocalls to apply--the government, not Twilio, determines who is legitimate. Existing robocall laws are too lax IMO, but it's a step in the right direction.

2. This is being proposed as part of legislation. All telecoms in the US would be required to implement the technology.

3. I don't think it's accurate to call it "open", but it's not centralized in the same way that Twilio's solution is. It's a federated system analogous to HTTPS certificate authorities. Twilio's service is more analogous to content filtering services like NetNanny. As I mentioned, CAs have problems too, but they're a whole lot more open than NetNanny.

Looks cool but wouldn't it be cheaper and easier to just outlaw robocalling like the rest of the world has?

I'm not a lawyer, but my understanding is that robocalls already fall under laws that make them illegal. The problem is that if someone makes an illegal call from a spoofed number, you can't tell where the call is actually coming from, so you can't prosecute the caller. SHAKEN/STIR closes the loophole that allows spoofing phone numbers.

Make the user-facing telco liable for any spam call. The industry will sort out the problem overnight, by disconnecting from the bad carriers from which spam calls originate.

That won't work, because with current technology it's impossible to tell where the calls originate from.

I'm not defending the telcos for dragging their feet on this issue, and I'm also not opposed to regulation, but there's a technological aspect to this problem which I think you're underestimating. The technology needs to be fixed before any regulation will be in any way enforceable.

The technology fix isn't something that can be implemented "overnight" either. If I'm understanding correctly, existing signing was implemented in hardware, because at the time it was implemented, that was the only way to get the performance necessary, and in the US most of the hardware the phone system runs on is legacy hardware. The solution has to be provably secure, support existing network hardware, support existing consumer hardware, be upgradeable, federate to avoid centralization, be agreed upon by all the telcos, be approved by regulators, and finally, be deployed without downtime. That's simply not going to happen overnight, and it's worth it to take the time to do it correctly rather than cutting corners on any of these steps.

Most robocalls are illegal in the US. We have a do not call list and everything. I believe is it a name change is currently working its way through to change the name to "seriously, do not call... please list". [https://www.forthepeople.com/class-action-lawyers/robocallin...]

The problem is that determining the source is difficult and even if you did it is most likely over seas where enforcing the fine is impossible.

I would love to hear a technical solution that has been implemented somewhere that had a significant impact.

There is a simple economic solution. Make the caller instead of the receiver pay for all calls.

This doesn’t work either. In india, calls are exclusively paid for by the caller but the number of unsolicited calls (and texts) is high.

The bigger problem is if they're scammers they wont care about a do not call list.

The telephone network is international. The US is limited in its ability to enforce anti-spam laws against operations running out of other countries. (They also seem unwilling or unable to enforce these laws domestically, but that's a completely separate issue.)

In this case I think it's a case of being unable to enforce the laws, because the technology for verifying callers is broken, making it easy to spoof phone numbers--even the US government doesn't know who is calling you illegally. SHAKEN/STIR is intended to close the security hole and make caller ID accurate again.

What are the technical hurdles to guarantee that only phone calls originating from the United States are identifiable with a US country/area code?

TL;DR is that it's "unwilling by way of almost unable".

The cooperation needed between telcos, who already have overly complex and archaic internal systems to manage themselves, would be almost impossible to coordinate.