Isn't it a pity they did not choose a safer language?
Opening up ‘Zero-Knowledge Proof’ technology
171–180 of 217 posts
Re: Opening up ‘Zero-Knowledge Proof’ technology
#172Earlier quoted context omitted.
I hear you. The main problem is how to prevent you from giving your document to somebody else, and things have converged on certified smartphone with security key plus biometrics.
Yeah, Passkeys are doing the same thing, expecting users to just blindly trust American Big Tech companies. It's distressing that no one working on these protocols considers the developers of the software that implements the protocol to be a party in the protocol. What are the wallet provider's interests in this exchange? How can the user be protected from the wallet provider? Seems no one asks these questions :(
Anyone can implement passkeys. The feature where passkeys can be made to attest to the hardware provider is optional and no site I've used requires it. Firefox defaults to not allowing passkeys to attest to the hardware unless you click through a permission dialog.
Re: Opening up ‘Zero-Knowledge Proof’ technology
#173For the sake of sanity - do never rely on Google when building critical sections of your software!
Re: Opening up ‘Zero-Knowledge Proof’ technology
#174Anyone have a good explanation on the intuition of non-interactive zero-knowledge proofs? For example, I thought the "paint-mixing" analogy for Diffie-Hellman key exchange ( https://en.wikipedia.org/wiki/Diffie–Hellman_key_exchange#Ge... ) really helped me handwave the math into "mixing easy, unmixing hard". https://blog.cryptographyengineering.com/2014/11/27/zero-kno... was a good intro for interactive ZK proofs but…
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Re: Opening up ‘Zero-Knowledge Proof’ technology
#175Age assurance will be the gateway to government issued(via corporate proxy) internet usage permits.
True, but I'm also not convinced that a ten year old being able to be face to face with hard-core BDSM and incest fetish porn within 40 seconds of opening a web browser is healthy. I don't like this but don't have another solution other than the porn industry self-policing which isn't promising.
The parents bare the responsibility. Don't baby-proof the Internet, the same way we are not baby-proofing the streets, subways or anything else.
Re: Opening up ‘Zero-Knowledge Proof’ technology
#176Earlier quoted context omitted.
The role of the secure element is only to "bind" the credential to the device, so that if you copy the credential somewhere else then the credential is useless. Concretely, the secure element produces a ECDSA signature that must be presented together with the credential. This is the normal protocol without ZKP. Concretely, the SE is in the phone, but could be a yubikey or something else. The ZKP library does not run…
Am I correctly understanding that I'd get the credential from say my state DMV once, and then later whenever I want to prove my age to a website the proof protocol is just between that website and my device? The DMV gets no information about what websites I use the DMV credential with and they get no information about when I use the credential even if the website and the DMV decide to cooperate? All they would be abl…
You are correct. The property that the colluding website and DMV still cannot identify you is called "unlinkability" and as far as I can tell cannot be achieved without zero-knowledge proofs. See https://github.com/user-attachments/files/15904122/cryptogra... for a discussion on this issue.
However, the timing attack resurfaces once you allow the DMV to revoke credentials. Exactly how the revocation is done matters. We are actively pushing back against solutions that require the DMV to be contacted to verify that the credential has not been revoked at presentation time, but this is a very nuanced discussion with inevitable tradeoffs between privacy and security.
Re: Opening up ‘Zero-Knowledge Proof’ technology
#177How do you defend against someone who: - Buys or borrows a laptop / phone / whatever from somebody with an authorized private key - Downloads an authorized private key file from a sketchy forum (maybe hacked from an unwilling target, maybe willingly shared by a free-speech advocate) - Uses a VPN over HTTPS to visit websites in countries where age checks aren't legally mandated (and non-compliance is implicitly or exp…
You do not. These measures are targeted against law-abiding and productive citizens to control them further. The other ones (the top 0.1% or the bottom 20%) are uncontrollable anyway.
In the future, you'll need a signed certificate with your PII/KYC to access the internet and get an IP address. China is already on the way there and the west is warming up to this approach.
Re: Opening up ‘Zero-Knowledge Proof’ technology
#178Earlier quoted context omitted.
The credential ("driver's license") contains a public key whose secret key is stored securely in a hardware secure element. The standard assumption is that the SE is in the phone, but it could be a yubikey or similar device. In order to use the credential, you need the SE. So you cannot buy a phone from somebody and download a credential from somebody else. You can however buy a phone and the credential from somebody…
> the SE is in the phone, but could be a yubikey or something else Just like with passkeys or MFA, the "something else" could be purely software though, right? And hence automated? For example I can run Windows 11 in a virtual machine on Linux, using softu2f to emulate TPM 2.0, and Windows does not know the difference.
The problem that needs to be solved is, how can a government give you an identity document in a way that you cannot give the document to somebody else. Whether or not this problem needs to be solved is a political question, but it seems like the majority thinks that identity documents should be hard to forge, in the same way as dollar bills should be hard to forge. The only practical solution is to have some sort of hardware that the user cannot forge, and relying parties will insist that the document be bound to such hardware. So yes, the something else could be software, but nobody will accept signatures from an emulated TPM. I had in mind a government-issued yubikey that can be identified as such, or maybe a plastic card with embedded secure chip with the same functionality. See https://github.com/eu-digital-identity-wallet/eudi-doc-archi... for the current thinking at least in the EU.
I should also remark that the above is a western-centric perspective, whatever "West" means. For example, I heard the architect for a similar system already deployed in India remark that in his jurisdiction many households share one phone across many family members, and India chose to accept more possibility for fraud in exchange for wider usability by the population. In that context this choice looks like the correct solution.
Re: Opening up ‘Zero-Knowledge Proof’ technology
#179A cool technology that builds on ZK is zkTLS that can prove that you have access to some data on the internet, for example that you have an account with some service without revealing your username. So more private oauth I suppose?
Reclaim Protocol, a YC company, is building an open sourced version for zkTLS. This has been by far the most widely adopted zkTLS project.
You can read the docs and whitepaper here: https://docs.reclaimprotocol.org/ And also take a look at all usecases built on top of this tech: https://reclaimprotocol.org/ecosystem
Re: Opening up ‘Zero-Knowledge Proof’ technology
#180> In layperson’s terms, ZKP makes it possible for people to prove that something about them is true without exchanging any other data. So, for example, a person visiting a website can verifiably prove he or she is over 18, without sharing anything else at all. But how does it prove that the request is actually made by a person and not a bot? Surely that part is technically impossible right now?
The government gives a signed document to natural persons, and the ZK system proves that the document is signed by the government. Bots don't have passports or driver's licenses.
How does the government guarantee that the natural person is such? Various jurisdictions will decide what's good enough, but as a strawman proposal, you go in person to city hall once and upload a document to your phone.