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Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

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Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#181

Post by AnthonyMouse »

Paracompact wrote: post #121
Gigachad wrote: post #60

Earlier quoted context omitted.

It's definitely not just kids. Social media is a lot like meth, we should at a bare minimum stop giving it to kids as soon as possible. And then come to realise it's bad for everyone and should be wound back.

Their argument would be, "If meth is a negative externality, we should just tax it instead of banning it in stores for kids to buy." Kids may die, but I'm sure with all that extra state revenue we'll get a nice park or museum or kickback to Tesla or something.

> Kids may die, but I'm sure with all that extra state revenue we'll get a nice park or museum or kickback to Tesla or something.

The argument, which has some pretty decent evidence behind it, is that prohibition is the thing that kills people. Because it has to be smuggled, dealers switch from "normal" hard drugs to overdose triggers like fentanyl with 1000x the potency because then they only have to smuggle 0.1% as much of it, which in turn kills people because street dealers cut it improperly and users get wildly different effective doses or drugs cut with dangerous contaminants.

Notice that meth literally is legal in the US. Essentially anyone can get amphetamines by going to a doctor and telling them you have the symptoms it gets prescribed to treat. It's even prescribed to kids. The primary barrier is having health insurance and the ability to take off work during the day every month to get a refill. Which is why the people dying of overdose are the people priced out of that system, who wouldn't be if they could buy it at Walmart, but because they can't they resort to the entirely unregulated black market and die of a fentanyl overdose.

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#182

Post by ulrikrasmussen »

rstuart4133 wrote: post #130
Groxx wrote: post #13

I'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? Good point, they do contain more information than "They are over 18". The primary (usually only) thing is who is attesting they are over 18. That might be the government, or a bank. That's inevitable, because the usual flow is rather like Google's OAuth - the site needing you to prove your age rediects to the provider (Google, or whoever), who asks questions…

> the usual flow is rather like Google's OAuth - the site needing you to prove your age rediects to the provider (Google, or whoever), who asks questions to verify your identity, and then replies with "over 18" or "not over 18".

This is false. There are many problems with age verification, but the EU approach does not involve the id provider in the verification flow. The site requiring verification presents a QR code which encodes a presentation request and the provider controlled URL which is to receive a presentation of the age credential, and then the smartphone generates a unique presentation signed by a device bound key and sends it to that endpoint.

It is however true that in addition to the one bit of information saying age>18, what is also revealed is the public key of the identity provider. This will at least reveal the nationality of the credential holder and - in the case there are multiple issuers within a nation - may reveal even more information about their demography.

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#183

Post by jonathanstrange »

brigandish wrote: post #172

Someone else in the thread asked, as others have, but most pithily > How about not needing to do age verification? Which I agree with. However, I think that ship is sailing. Those who care about this had better find a provider that they trust and support providers they trust, because the perfect is the enemy of the good, and without the good there'll be no way to rollback to the perfect at all .

The people who are against this do not trust any of them for good reasons, so that ship has sailed long ago, too.

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#184

Post by ortichic »

Lots of bias in this thread. But maybe we can have a technical discussion?

I'm not into this topic, so maybe someone else can answer this: How "zero-knowledge" is this actually?

As far as I understand, there are three parties here: 1. Me, the user; 2. The site I want to access; 3. The attestor (google? my government?). What do they know about each other?

Does the site know who I am?

Does the site know who my attestor is (and therefore, for example, that it doesn't like Winnie-the-Poo memes)?

Does the attestor know what site or kind of content I want to visit (and therefore e.g. if he agrees with it)?

Does the attestor know who I am?

Do I always know who the site and attestor are, and when this proof happens?

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#185

Post by khalic »

elcritch wrote: post #180
grey-area wrote: post #106

Earlier quoted context omitted.

Yes, a lot of it involves denigrating women and an entitled and very rigid attitude towards the male place in society (alphas etc). This is incredibly toxic for young men growing up and the women they interact with. Some of the more prominent proponents are actual pimps (the Tate brothers).

How is that different than pervasive pornography though? Many young boys now think it’s normal to ask girls for sexual acts before having ever kissed a girl.

Seems like they could use some sex ed courses

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#186

Post by bigfishrunning »

semi-extrinsic wrote: post #84
stephen_g wrote: post #15

Earlier quoted context omitted.

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…

It seems to me that the technical people who get invited to public debates are simply not competent or knowledgable enough. We definitely need to step up! But a part of me wonders if this may be by design from the debate moderators - if a technical expert opens up by saying "we have a cryptographically secured solution that is backed by experts and privacy advocates alike", what's the next 45 minutes of the TV show g…

The same thing every 45 minutes of every TV show is about -- selling cars and mattresses.

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#187

Post by hoppp »

ortichic wrote: post #184

Lots of bias in this thread. But maybe we can have a technical discussion? I'm not into this topic, so maybe someone else can answer this: How "zero-knowledge" is this actually? As far as I understand, there are three parties here: 1. Me, the user; 2. The site I want to access; 3. The attestor (google? my government?). What do they know about each other? Does the site know who I am? Does the site know who my attestor…

Its not really possible to know.

the system is valid zkp but any of the services in practice can still collect personally identifiable information from their users.

There is also nothing stopping the attestor to collude with the site you want to access, to reveal information about you.

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#188

Post by ongy »

ortichic wrote: post #184

Lots of bias in this thread. But maybe we can have a technical discussion? I'm not into this topic, so maybe someone else can answer this: How "zero-knowledge" is this actually? As far as I understand, there are three parties here: 1. Me, the user; 2. The site I want to access; 3. The attestor (google? my government?). What do they know about each other? Does the site know who I am? Does the site know who my attestor…

I tried to find something definitive, but it would take more time than I have right now. So to some degree this is assumptions, though generalized.

* Does the site know who the user is: No. That's the entire purpose here.

* Does the site know who the attestor is: Yes, they need to validate asymmetric crypto on the proof, so they need a list of public keys (which they can attach attestor identity to).

* Does the attestor know what kind of content I want to visit: They should not. With the JWT you can validate without telling the attestor which user's proof you validate. OTOH, if there's some "is this one revoked" type of API one could easily re-introduce such an information channel on accident.

* does the attestor know who the user is: Yes (or at least have some bits of information about you they are willing to attest to others. In practice assume it's Google/Apple/MS with information associated with your account, or your bank or ...)

* Does the user always know site/attestor: From a technical perspective yes. From a practical human one... doubtful.

--Googler, though far removed from this project, so no internal knowledge.

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#189

Post by mindslight »

Aurornis wrote: post #23
Groxx wrote: post #13

I'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 anonym…

> 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.

SPOT ON! This needs to be plastered across the top of every single thread on "age verification" (really: identity verification).

Talk of "zero knowledge proofs" or other technical schemes are essentially just nerd sniping on this topic. These sound like really cool solutions where we can have our cake and eat it too, but the reality is that the cool technical bits are just the tip of the iceberg. For them to actually be secure (ie prevent the trivial proxying of credentials), there has to be another, much more draconian, part to the system.

Even if that part is missing to begin with, then calls to add it down the line will be inevitable once the idea that websites are responsible for verifying users "ages" (identities) has taken hold and those flaws become glaringly apparent.

I am a parent who will be staring down this issue in a few short years. The Internet is not the place we grew up. Faceboot and other engagement-farming companies are most certainly malevolent threats to the human psyche [0], and it's reasonable to assume that their effects are even stronger on developing minds.

The only approaches that are workable to protect kids as well as preserve Internet/computing freedom (which is actually an additional angle of protecting kids from continuing loss of freedom to roam) involve the client device being responsible for what to block/show, with information only ever flowing from the server to the client - for example tags that assert a site/app is suitable for people over a given age, and on-device parental control software that operates on those tags. If parental controls are enabled and a website has no tags, then the site does not display - failing closed and preserving compatibility with the open web.

Given that this is a dire problem that parents face that has reached a tipping point, it would be reasonable to create a legal mandate that mass market device manufacturers must include parental control software that can be enabled during setup process, and that websites over a certain size have to include tags stating their age appropriateness. That would bootstrap the ecosystem and lead to the development of more vibrant tags and blocking software, enabling parents to set their own policies independent of corporate attorneys decreeing what is acceptable for their kids.

[0] It is also worth keeping in mind that it is exactly Faceboot and its ilk that are pushing these identity verification laws in the first place! They are simply trying to remove their legal liability for harming kids, so they can otherwise continue business as usual

Re: Opening up 'Zero-Knowledge Proof' technology to promote privacy in age assurance

#190

Post by abricq »

ortichic wrote: post #184

Lots of bias in this thread. But maybe we can have a technical discussion? I'm not into this topic, so maybe someone else can answer this: How "zero-knowledge" is this actually? As far as I understand, there are three parties here: 1. Me, the user; 2. The site I want to access; 3. The attestor (google? my government?). What do they know about each other? Does the site know who I am? Does the site know who my attestor…

I'm not an expert either, but i've studied it a little and tried some of these stuffs.

First, the attestor is not google. Google here only provides the infra (to generate proof and verify them). Let's call the attestor the issuer, and it's the trusted authority that gives you a proof of identity.

A possible flow is:

1. (pre-req) Some issuer (a state, bank, mobile operator, etc.) issues a signed credential to my wallet (stored on my phone, for instance). This could be a full digital ID, or a narrower “proof of age” attestation.

2. Later, a site asks my browser for a proof that I satisfy some predicate, e.g. age >= 18. The site provides the "zk-program" (circuit) that needs to be executed, and awaits for proof (which are essentially proof of executions of the program on trusted yet undisclosed inputs).

3. My phone generates (ideally locally, but not ready today yet) a ZK proof that it knows a valid issuer-signed credential whose hidden attributes satisfy that predicate. Essentially, it is executing the circuit with some inputs (some are public, like public key of issuers, some of private, like the issued ID)

4. The site verifies the proof against public inputs: the issuer public key, the circuit being used, the predicate being requested, and a fresh nonce/challenge.

So to answer some of your questions.

> Does the site know who I am? Not from the ZK proof itself, it will know who has issued your ID.

> Does the site know my attestor? Yes, it knows their public key.

> Does the attestor know what site I am visiting? No.

> Does the attestor know who I am? Yes

> Do I know who the site and attestor are, and when proof happens? I guess there are multiple possible ways to do this, depends on the UX.

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