> It derives an age attribute such as "over 18" from a passport or ID, without disclosing any other information such as the date of birth.

How? If it’s analyzes my ID 100% client side I can fake any info I want. If my ID goes to a server, it’s compromised IMO.

I think the zero proof systems being touted are like ephemeral messaging in Snapchat. That is, we’re being sold something that’s impossible and it only “works” because most people don’t understand enough to know it’s an embellishment of capabilities. The bad actors will abuse it.

Zero proof only works with some kind of attestation, maybe from the government, and there needs to be some amount of tracking or statistics or rate limiting to make sure everyone in a city isn’t sharing the same ID.

Some tracking turns into tracking everything, probably with an opaque system, and the justification that the “bad guys” can’t know how it works. We’ve seen it over and over with big tech. Accounts get banned or something breaks and you can’t get any info because you might be a bad guy.

Does your system work without sending my ID to a server and without relying on another party for attestation?

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myrion 3 hours ago | parent | next [-]

There's no dynamic analysis done, necessarily. In the Swiss design, fex, SD-JWTs are used for selective disclosure. For those, any information that you can disclose is pre-hashed and included in the signed credential. So `over_18: true` is provided as one of those hashes and I just show this to the verifier.

The verifier gets no other information than the strictly necessary (issuer, expiry, that kind of thing) and the over 18 bit, but can trust that it's from a real credential.

That's not strictly a zero knowledge proof based system, though, but it is prvacy-preserving.

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bitmasher9 4 hours ago | parent | prev | next [-]

Attestation from government sounds like the ideal solution. This could actually provide _more_ privacy because we can begin using attestation for things we currently use IDs for such as “Has the privilege of driving a car” or “Can purchase alcohol”

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Aurornis 3 hours ago | parent [-]

Amazing how fast these systems go from "zero knowledge" to "route the request through the government system every time you use your ID"

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hiciu 2 hours ago | parent [-]

there is no "route the request through the government system every time you use your ID".

you get your sd-jwt document signed once and you reuse it for like 30 days or so.

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summm an hour ago | parent | next [-]

Technically, if your phone needs to be remote attested, it can be considered a government system, not a user's system.

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Aurornis 2 hours ago | parent | prev [-]

I was responding to the comment above mine, which was calling for attestation from the government for specific privileges.

> you get your sd-jwt document signed once and you reuse it for like 30 days or so

So it still gets routed through the government once a month if you plan on using it.

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hiciu 2 hours ago | parent [-]

Yes we are still talking about attestation from the government for the specific privilege part.

You get your document with fields like "can drive", "is over 18" and so on. It's valid for some time; physical ID is valid for like 10 years and then you have to get a new document, this digital one is valid for lets say 30 days and if it expires you get a new one.

Then you present only those fields you want, when you want, without anyone talking to the government at all. All the other party needs to check is "is the document valid" and "do presented fields match the document". Like checking a tls certificate for a given domain name or purpose.

Strictly speaking there is no "routing through the government" of any information. The government just "issues a certificate" valid for X days without knowledge with whom, how or when you are using it.

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Aurornis an hour ago | parent [-]

> Strictly speaking there is no "routing through the government" of any information. The government just "issues a certificate" valid for X days without knowledge with whom, how or when you are using it.

I don't understand how you keep claiming there is no "routing through the government" right next to your explanations that the government is the one providing the documents every 30 days.

Obviously something in the document is tied to your ID and the government has mechanisms to revoke it. No matter how many layers you put on top of that, this all has to come back to the government's control.

I understand that the salts can be sent to 3rd party websites. However there's obviously a reason that those are only valid for 30 days instead of indefinitely.

	▲	hiciu 39 minutes ago \| parent [-]
		Yes, something in the document is tied to my ID. There's my name in there for example :). I don't have to share that information, because what government signed is a uniquely salted hash of my name and passed the salt to me. If I choose to share that salt, and provide my name, someone could hash all that information and compare it to the government-issued document to verify if my name really is john smith (or if my claim "I'm over 18" is valid). If I don't, they have no way of knowing. > no "routing through the government" > government is the one providing the documents I'm also lost. I mean, this is the government issued ID we are talking about, right? How are you expected to get it if not from the government? "Are you over 18" claim is part of that government issued ID. They don't have to know which sites or when you are visiting, but they do have to issue you the document. (To be clear, there are also other options, it doesn't have strictly to be government; for example banks around here can provide ID documents - for their clients. There's a list of who is trusted for what https://eidas.ec.europa.eu/efda/trust-services/browse/eidas/...). > However there's obviously a reason that those are only valid for 30 days instead of indefinitely. It's the same reason why we prefer tls certificates with short lifespans.

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runako 4 hours ago | parent | prev [-]

> If it’s analyzes my ID 100% client side I can fake any info I want. If my ID goes to a server,

amplifying your point, there is effectively no way for the layperson to make this distinction. And because the app needs to send data over an encrypted channel, it would be difficult at best for a sophisticated person to determine whether their info is being sent over the wire.