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Opening up ‘Zero-Knowledge Proof’ technology

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Re: Opening up ‘Zero-Knowledge Proof’ technology

#201

Post by coldpie »

AgentME wrote: post #172
coldpie wrote: post #82

Earlier quoted context omitted.

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.

I don't want to get into a Passkey derail, but no. The Passkey spec requires clients to handle the user's own data in certain ways, and the Passkey spec authors threaten clients that allow users to manage their own data with client bans.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#203

Post by [deleted] »

coldpie wrote: post #200
MatteoFrigo wrote: post #176

Earlier quoted context omitted.

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.…

>> 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? > 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. Well, no. This is true only if y…

[deleted]

Re: Opening up ‘Zero-Knowledge Proof’ technology

#204

Post by geodel »

gmueckl wrote: post #65
regularfry wrote: post #50

Earlier quoted context omitted.

Do you happen to know what the answer of this scheme to "I have a wireguard connection to another country, you can't see my traffic" is? I know that enough of the population would never bother so it wouldn't significantly harm it as a revenue scheme, but if your goal is avoiding identification rather than taxation then the stakes could be high enough to make the effort worthwhile.

The political answer to circumventing laws is usually some form of punishment. This is often much easier than weird technical solutions.

Indeed. Governments have to worry about 99.9% of cases covered with a law or regulation have punishment in term of fine or imprisonment.

Those remaining very likely have multiple advantages like advance technical knowledge, connection to powerful people in business / governments, money and legal support in case they end up on wrong side of law. There is very little benefit and lot of effort to catch these unless they are running some kind of criminal organization which adversely affects their government/regime.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#205

Post by nixpulvis »

MatteoFrigo wrote: post #183
nixpulvis wrote: post #164

Earlier quoted context omitted.

Would something like this be considered a ZK proof? https://crypto.stackexchange.com/questions/96232/zkp-prove-t...

No. ZK has a technical definition I don't want to get into, but note that the described system is deterministic and it always produces the same proof for Alice on a given day, and the proof for a later day can be derived from the proof for an earlier day. So two proofs can be linked back to Alice, and thus the system is not ZK. You need some kind of randomness for ZK.

Makes sense.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#206

Post by tzs »

coldpie wrote: post #200
MatteoFrigo wrote: post #176

Earlier quoted context omitted.

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.…

>> 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? > 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. Well, no. This is true only if y…

MatteoFrigo is suggesting that unlinkability requires ZKPs.

Your observation that a bad wallet could compromise unlinkability is not a refutation of that. To refute it you need to show that it is possible to achieve unlinkability without using a ZKP.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#207

Post by coldpie »

coldpie wrote: post #199
MatteoFrigo wrote: post #182

Earlier quoted context omitted.

See https://github.com/eu-digital-identity-wallet/eudi-doc-archi... for a reference to the nuances on all these topics, at least in the context of the European Union. Other locales have different problems and different solutions. If you think you have a better idea shoot me an email.

The document states: > Controlled by users: The EU Digital Identity Wallets will enable people to choose and keep track of their identity, data and certificates which they share with third parties. Anything which is not necessary to share will not be shared. I think where the ZKP stuff being discussed here fails to meet this criteria is the wallet provider is also a third (non-user) party. You stated elsewhere that a…

Update: After some email discussion with Matteo, it looks like my fears are unfounded. The EU regulations seem to require wallets to be open source[1]. Assuming that wallets do not need to pass any sensitive transaction data down to the OS libraries, then it should be possible for users to verify the behavior of their wallet software by examining the source and possibly even by building & deploying it themselves.

[1] See section 33 here https://www.european-digital-identity-regulation.com/Preambl...

Re: Opening up ‘Zero-Knowledge Proof’ technology

#208

Post by randomNumber7 »

I'm so tired of old closed minded people that run EU countries since ever.

I know someone in germany that got detected cancer in an MRI scanner. The doctor gave him the images and told him to drive to a specialized hospital ~400km away. Otherwise they would send it there with a physical mail and the treatment would have started a week later.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#209

Post by mullingitover »

krunck wrote: post #4

Age assurance will be the gateway to government issued(via corporate proxy) internet usage permits.

Today it's age gating porn, but the next move will be age gating sites that talk about LGBTQ issues by moving the 'obscenity' definition to be anyone they don't like. Left to their own devices and unopposed, they'll declare discussion of birth control and interracial marriage to be adults-only.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#210

Post by SavioMak »

JanisErdmanis wrote: post #84
bobbiechen wrote: post #29

Anyone 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…

An intuitive explanation is that of proving you can find Waldo in a picture without revealing his exact location. Digital wallets can be interpreted as fancy signature schemes that operate on third-party issued commitments C instead of public keys that directly link users to their identities. A simple signature scheme is based on proof of knowledge PoK{x : pk = g^x}, which is transformed into a noninteractive variant…

Sorry but that is not intuitive for me. You wrote one line of analogy and then went into 4.5 paragraphs of technical explanation.
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