We need "How to talk to your legislators about zero-knowledge proofs".
"Dont do age assurance, ever" Done.
"Do the opposite of what Meta is lobbying for"
Done.
Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
21–30 of 302 posts
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#22Zero-knowledge seems to be a bit of an oversell here. It is more like you break the knowledge up and only share the relevant parts with each party. And the facilitator (Google) arguably has access to the most information out of any of the parties involved.
zero-knowledge proofs are a well-known tool in cryptography [1]. All Google is sharing is the library to implement it. Google would not have access to the information any more than they have access to the bank info of people who use Android or Gmail. [1] https://en.wikipedia.org/wiki/Zero-knowledge_proof
It's my understanding that they are sharing the library but they will also be involved as a facilitator, at least to the extent that people use their identity wallet service. It also seems like they will have access to who you are sharing information with, which seems like the most valuable information for a company in their position, with nothing but a pinky promise that it will not be tracked. Let me know if any of that is inaccurate.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#23I've been trying to figure out how zero-knowledge stuff would work in practice for age verification, where "when issued" (or extremely coarse, like what year), "to whom", and "where it's used" are hidden from everyone except the individual holding the proof (since that's the gold standard, and the only one worth accepting). I get that ZK techniques work, and reveal "nothing". That's useful. But if they reveal nothing…
> But if they reveal nothing, isn't it wide open for abuse? Couldn't one over-18-person's proof become everyone's proof, because they can't tell it's the same proof, and the issuer can't tell where or how often the proof is being used?
Yep!
This is why the concept of zero knowledge age gating is such a trap for technically minded people. They imagine receiving a private cryptographic object that can be used to anonymously confirm that the government says it was issued to someone over 18.
That’s completely useless because a single leaked token could be used forever, so nobody actually considers this.
All of the real proposals have various compromises baked in. Some people want to require device attestation, so you could only do this handshake from a government approved device running a government approved operating system. Forget using Linux or maybe even a general purpose computer at all.
Other proposals involve online government handshakes in various ways, with a pinky promise that the government won’t keep logs or tap it for national security purposes. So we get back to anonymous by trust only.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#24Zero-knowledge seems to be a bit of an oversell here. It is more like you break the knowledge up and only share the relevant parts with each party. And the facilitator (Google) arguably has access to the most information out of any of the parties involved.
Ideally the government would be the issuer and the facilitator but the US lacks the state capacity to do this. Maybe it will work that way in Estonia.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#25I've been trying to figure out how zero-knowledge stuff would work in practice for age verification, where "when issued" (or extremely coarse, like what year), "to whom", and "where it's used" are hidden from everyone except the individual holding the proof (since that's the gold standard, and the only one worth accepting). I get that ZK techniques work, and reveal "nothing". That's useful. But if they reveal nothing…
This is basically the double spending problem which has been solved in various ways.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#26I've been trying to figure out how zero-knowledge stuff would work in practice for age verification, where "when issued" (or extremely coarse, like what year), "to whom", and "where it's used" are hidden from everyone except the individual holding the proof (since that's the gold standard, and the only one worth accepting). I get that ZK techniques work, and reveal "nothing". That's useful. But if they reveal nothing…
This is basically the double spending problem which has been solved in various ways.
It has? I've been under the impression that the "solutions" are "trust us, we don't allow that" (relying on an authority with full knowledge, as partial knowledge isn't sufficient) and "use more resources than anyone can feasibly contest" (bitcoin).
You could build a merkle tree to say "we exist after X" but not "there is no other X". And publishing that tree for verification would seemingly violate "zero knowledge", unless you know of some way to scrub that, and also hide timing information, because timing information can identify visitors to observers.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#27I've been trying to figure out how zero-knowledge stuff would work in practice for age verification, where "when issued" (or extremely coarse, like what year), "to whom", and "where it's used" are hidden from everyone except the individual holding the proof (since that's the gold standard, and the only one worth accepting). I get that ZK techniques work, and reveal "nothing". That's useful. But if they reveal nothing…
Idk if this scheme is zero knowledge, but what's wrong with it? :
- you enter ph and must age-verify. It says 'your secret: "capable peanut", enter age proof below'.
- you go to age-knower (e.g bank or government page). You provide the secret phrase, and you get back a cryptographically signed json with the secret phrase, a claim 'above18', and a field stating who attested for the age (e.g government or bank or whoever).
- you paste this signed json (maybe encoded as base64 or something) into ph. It will verify that the attestee is good, then use it's public key to verify the signature, before checking that the secret is the correct one, and that it contains the age-claim.
Is the problem that if ph and the attestee colludes they can compare the secret string and figure out who you are?
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#28Unfortunately ZKP's aren't magic.
When not doing privacy oriented cryptocurrency (cough money laundering cough) with ZKP's, if you really want private verification you are in a position where a single actor can authenticate the entire world and no one will know it happened. And to prevent it you assemble the pieces necessary to deanonymize anyone.
Make no mistake. ZKP age verification, as proposed, will just require multiple parties to collude to figure out your identity.
They can't even implement ZKP for remote attestation due to the auth-the-world problem.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#29Earlier quoted context omitted.
Yes, but it's never been more important than now. Also, I did not have enough chars for an HN title.
Funny though how whenever these laws are pushed though, the legislators are more interested in strongly identifying people to gate services despite the fact that they should have plenty of advice that things like zero-knowledge proofs exist. I hate to be cynical but I worry that this isn't going to matter, because it really seems that a lot of the pressure behind age verification isn't actually very interested in the…
Agreed. Now is our chance to very publicly inform our legislators. Not all is lost, yet.
Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance
#30Unfortunately ZKP's aren't magic. When not doing privacy oriented cryptocurrency ( cough money laundering cough ) with ZKP's, if you really want private verification you are in a position where a single actor can authenticate the entire world and no one will know it happened. And to prevent it you assemble the pieces necessary to deanonymize anyone. Make no mistake. ZKP age verification, as proposed, will just requir…
Assuming that perfect is the enemy of good, this is still better than all the proposed alternatives, isn't it?