Balaji Profile picture
Sep 20, 2020 11 tweets 2 min read Read on X
With respect to proof of location, you can’t naively use GPS because it can be spoofed. You might go with trusted towers of known location, but that’s centralized.

Another approach may be to assume K of N nodes are honest reporters of GPS, and use speed of light as a constraint.
Specifically, suppose you have N nodes, each of which is reporting a time-varying position [x(t), y(t)] over a time interval with M time steps.

Any node which purports to be near another node can be challenged by an equation that it must solve & return as quickly as possible.
For a pair of nodes with reported locations, the speed of light gives a lower bound on how quickly info can go back & forth.

Obviously network topology can dramatically change ping times. But a node should be able to solve more challenges more quickly from nodes it’s nearer to.
A node that claims to be at a given (x,y) location at time t will get many challenges from other nodes that report being near to it at time t.

It’s incentivized to solve and return these challenges as quickly as possible, such that compute time is small relative to ping time.
Some nodes in the network would be stationary while others would be phones or tablets.

The protocol wouldn’t be hardcoded to trust any particular node, but stationary servers run by organizations like Pingdom or PagerDuty could accumulate many location confirmations over time.
So, you might not get a *guaranteed* location out of it. But you might get something like “this node was close enough to stationary servers operated by different entities to pass many challenges over this time interval, meaning it was likely within this coordinate ball.”
Importantly, if you ran an organization, you could put your *own* servers on the network with fully trusted and known locations. And you could prioritize the response to their challenges when looking for nodes with spoofed locations.
This is a form of independent verification. If you introduce probes with known-to-you locations that issue challenges to other nodes — and yet the reported location of other nodes doesn’t change — that’s good evidence the protocol is working.
Incentives TBD, but roughly speaking you’d want to incentivize nodes that had high uptime, reliable locations, and the compute to issue and pass many challenges. And you’d want to slash or penalize nodes that spoofed their location.
Finally, it goes without saying that ping times are a highly imperfect measure of physical distance.

They can rise for reasons like network congestion that have nothing to do with a node moving further away.

Nevertheless, they are lower bounded by the speed of light.
What about VPNs? These are tricky for distance-based methods because you’re remote controlling a computer (with some latency) that actually is physically in the claimed region.

You might make the challenge depend on a private key which you wouldn’t want to copy to the VPN node.

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More from @balajis

Feb 17
I just got back from Prospera.
A startup city on the island of Roatán.
It’s crypto, it’s bio, it’s robo.
And it’s not San Francisco.
We’ve started new companies, new communities, and new currencies.

Now we’re starting new cities.
My body, my choice.

That’s what personal medical sovereignty means.

If you can legally go skydiving or bungee jumping, you should be able to take a calculated risk on new treatments.

And that’s what Prospera has legalized.
Read 4 tweets
Jan 21
We now understand the 2010s.

It’s when legacy media fought a ferocious but ultimately doomed rearguard campaign against the Internet.

That’s why they pushed censorship so hard and constantly thumped their chest about being “journalists.”

It was protectionism.
They were dying.
Image
Many journalists spent the better part of a decade attacking the Internet for a living.

You understand it better when you realize it was existential for them. They didn’t just lose money, they lost power.
Even legacy media now admits it. Trust in newspapers has collapsed. Image
Read 5 tweets
Nov 16, 2023
1) Ban China
2) Be China
3) Beat China

These are the options. I get the logic, but banning signals technological and cultural weakness. Yet so does capitulation of the Newsom variety. The best way is to build something *better* than China, as Elon and others in tech have done.
Image
Democrat concern about Russia is similar to Republican concern about China.

I get where it comes from. But the real answer is to build a more compelling product that can win on the global internet.

Otherwise you're giving up on soft power.
Why isn't China submissive anymore?

The unspoken truth: because they don't respect America anymore. For example, they feel they can build better cities than the US.

The best way to prove them wrong is to outbuild them.
Read 5 tweets
Nov 15, 2023
Democrats cleaned up San Francisco for Communists.
Newsom admits they removed the drug addicts for Xi.

“That's true because it's true.”
And don’t let them pretend this was just like cleaning up before some friends come over!

We are talking poop, needles, syringes — raw sewage on the streets.

And we are talking about addicts, thieves, and arsonists.
Read 8 tweets
Nov 6, 2023
Congress blew him kisses.
Journalists gave him applause.
Regulators promised to take no action.
So it was only Crypto Twitter that uncovered his deception.

Read the actual history of what happened with Sam Bankman-Fried, before it gets memory holed.
balajis.com/p/crypto-twitt…
Meanwhile, Coindesk's Ian Allison was revealing[1] that SBF had no money, while Axios' Dan Primack was asking[2] whether SBF could cure world hunger.

[1]:
[2]:

archive.ph/y7YOi
archive.ph/nlYCj
Remember when Bankless was playing hardball with SBF[1], while Joe Weisenthal was throwing him softballs[2]?

Dunno why @thestalwart is tweeting from behind a block, but maybe you can ask him.
[1]:
[2]:
archive.ph/6Wl2t
archive.ph/wuwOp
Read 5 tweets
Sep 27, 2023
The Army War College thinks war with China could cause 3600 casualties per day. So, they're considering a draft. press.armywarcollege.edu/cgi/viewconten…
Image
One decade's worth of casualties in one week.

"For context, the US sustained about 50k casualties in two decades of fighting in Iraq and Afghanistan. In large-scale combat operations, the US could experience that same number of casualties in two weeks." press.armywarcollege.edu/cgi/viewconten…
Image
Others are making similar proposals, due to military recruiting shortfalls.

"...in 2023, every service except the Marine Corps is poised to miss its recruiting goals. In 2022, the Army alone fell short by 15,000 recruits."
military.com/daily-news/opi…
Read 5 tweets

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