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Opening up ‘Zero-Knowledge Proof’ technology

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Re: Opening up ‘Zero-Knowledge Proof’ technology

#131

Post by MatteoFrigo »

csense wrote: post #128

How 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…

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. As a mitigation, the SE only generates the signature when unlocked via a fingerprint or similar biometric input which must match the one that was provided at the time the credential was issued. Whether or not your attack works in this scenario depends on the details. For example, if you only obtain the credential in person at a local government office and provide a fingerprint at that time, it's not that easy to sell the phone and the credential afterwards.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#132

Post by icelancer »

abhv wrote: post #39
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…

My colleague Amit made a simple video explanation about zkp with Wired. https://youtu.be/fOGdb1CTu5c?si=EyBQS92WyeduIpH- That doesn't explain the way this scheme works, but it's a nice start.

Was looking to see if someone posted this video. The first few interviews are excellent - the later ones, not so much (in terms of explaining ZK - they're good chats, of course).

Re: Opening up ‘Zero-Knowledge Proof’ technology

#133

Post by prophesi »

heavyset_go wrote: post #61
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.

> 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? WG traffic is easily identifiable and able to be blocked, it's what happens in countries that ban VPNs.

At that point something along the likes of shadowsocks would be more effective, and the question still remains.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#134

Post by [deleted] »

MatteoFrigo wrote: post #131
csense wrote: post #128

How 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…

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…

[deleted]

Re: Opening up ‘Zero-Knowledge Proof’ technology

#135

Post by cma »

goopypoop wrote: post #122
deegles wrote: post #113

Earlier quoted context omitted.

for explanation i've seen for the where's waldo analogy: imagine the single page of the where's waldo puzzle, and another giant piece of paper with the shape of waldo cut out of it. by providing a picture of waldo in the cut-out, you can prove you know where he is without providing the location. a zero knowledge proof.

Is that "Draw a Waldo with this outline"?

Imagine it isn't Waldo, but an unknown figure and you are only given the silhouette to find. If you can draw what's within the silhouette or something, you've proven you've located it to high certainty without saying where.

Say the whole image looked like noise and was generated from quantum measurements, and the coordinates to hash for the problem were generated with quantum measurements, and you were given the silhouette and the hash of the noise within to look for. I could see it for proof of work: you could slide along a hashing window and prove you actually did work examining half the image on average or whatever.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#137

Post by orblivion »

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…

The explanation that one person gave me was basically that you use an RNG to generate the challenges. Not sure if this is quite "proper", but it makes sense to me so long as you can't game the system. Perhaps make the RNG slow to prevent picking a convenient sequence?

Re: Opening up ‘Zero-Knowledge Proof’ technology

#138

Post by burnt-resistor »

api wrote: post #8
krunck wrote: post #4

Age 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.

This is a parenting problem, not a technology and everyone else problem.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#139

Post by tzs »

coldpie wrote: post #109
ChuckMcM wrote: post #91

This is great. It really pissed me off when David Chaum locked all the cool uses of ZKPs behind a patent wall. The DigiCash folks were peak dot com greed types, their business model was "We're going to get big chunk of change out of every transaction ever so we should be valued at 1% of the worlds GDP!" And the world responded with "Yeah, no." I really like Andy Birrells "micro-cents" which exploited the fact you cou…

> This is great. Do you still feel that way knowing that it introduces a hard requirement for all users to have their private data managed by one of Apple, Google, or Microsoft[1]? I want to be excited about this, and about Passkeys, but the people working in this space keep fumbling this ball :( [1] " Using the MDOC requires a signature from a hardware security key in the phone " https://news.ycombinator.com/item?id…

You can have a password manage your passkey private data. Several now have passkey support, including some that work on Linux such as 1Password and Bitwarden letting you use passkeys even if your household is completely Apple-free, Microsoft-free, and Google-free.

Re: Opening up ‘Zero-Knowledge Proof’ technology

#140

Post by notfed »

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…

Intuition of what it is (ie interface) or how it works (implementation)?
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