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Programming Zero Knowledge Proofs: From Zero to Hero

zkintro.com

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Re: Programming Zero Knowledge Proofs: From Zero to Hero

#21

Post by rvrs »

LegionMammal978 wrote: post #19
nl wrote: post #10

Earlier quoted context omitted.

Actually this is only partially true (have implemented verifiable credientials and ZK on top). VCs will allow you to verifiably specify your date of birth or maybe your passport number. What ZK does is allows a third party to ask questions like "is the date of birth of this person prior to 2-Sep-2006" (ie, are they over 18) or "is this person a passport holder for country X" and the ZKP system can say yes or no witho…

> without disclosing the actual birthdate What prevents the birthdate from being gleaned through a simple binary search? Or, if it's specifically an "over 18 today?" query based on some decentralized timestamp source, what prevents the query from just being repeated every day until the result changes (assuming it returns "under 18" at first)?

The holder of the credential would have to present it log(N) times. If someone asks to scan your id a bunch of times, wouldn't you find it suspicious?

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#22

Post by Jerrrrrrry »

LegionMammal978 wrote: post #19
nl wrote: post #10

Earlier quoted context omitted.

Actually this is only partially true (have implemented verifiable credientials and ZK on top). VCs will allow you to verifiably specify your date of birth or maybe your passport number. What ZK does is allows a third party to ask questions like "is the date of birth of this person prior to 2-Sep-2006" (ie, are they over 18) or "is this person a passport holder for country X" and the ZKP system can say yes or no witho…

> without disclosing the actual birthdate What prevents the birthdate from being gleaned through a simple binary search? Or, if it's specifically an "over 18 today?" query based on some decentralized timestamp source, what prevents the query from just being repeated every day until the result changes (assuming it returns "under 18" at first)?

Just because someone asks, doesn't mean one must answer.

"Be liberal in what you receive, and strict in what you send."

The protocol would have to specify an authorized inquiry field or use validity by time, using a global consensus (current bitcoin block + challenges that take bitcoin_blocks block production rate on average to solve)

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#23

Post by tzs »

nailer wrote: post #3

> We can take a digital identity card and prove that we are over 18 years old > Without revealing anything else, like your full name or address If you are in this articles audience you would simply state the producer of the ID card signs a statement that the person is over 18. No ZKP needed. The article like many others would be improved with a better example.

I don't think a simple signature is sufficient if you want to maintain privacy with both the party you are trying to convince that you are over 18 and the party that signs the statement saying you are over 18.

If the signer keeps a copy of the signature and who they made it for, someone who gets a hold of that and the records of party you used the signature at they can find out who you are.

There are ZKP based protocols that allow for age verification where even if the party that attests to you age keeps records they do not find out where you are using that attestation, and the party you use the attesting with only finds out that you are above their age threshold and what attesting party you used.

I think that this can be done without ZKP if instead of simple signatures we use blind signatures.

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#24

Post by ironSkillet »

badsandwitch wrote: post #20
cosignal wrote: post #2

As someone with zero knowledge regarding Zero Knowledge Proofs in a programming context, can someone give me a basic explanation regarding the utility? I do understand the basic principle of ZKP’s, but as yet I’m failing to understand how this would be applied in industry.

It is currently possible to use ZKP's to set up via a central authority a digital cash system where the bank notes are all anonymous and all transfers are anonymous. The central authority in this scenario cannot discriminate between transactions - any function that would compare two or more transactions cannot glean any useful information that would allow to discriminate. And and security of the anonymity of past tra…

Do you have any recommended references on this subject? Seems like this sort of system would be able to obfuscate a lot of metadata that can be used to deanonymize activity. Very interesting.

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#25

Post by satchel888 »

baby wrote: post #12
cosignal wrote: post #2

As someone with zero knowledge regarding Zero Knowledge Proofs in a programming context, can someone give me a basic explanation regarding the utility? I do understand the basic principle of ZKP’s, but as yet I’m failing to understand how this would be applied in industry.

The way I always explain it to newcomers now is to start from digital signatures. Digital signatures are useful, we all know that, now imagine if you could sign not only data, but also computation result. As in “I ran this code with these inputs and it produced that output”. If you imagine that this would work, and it takes less time to verify that signature than running the program myself, you have a succinct proof.…

[dead]

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#26

Post by satchel888 »

badsandwitch wrote: post #20
cosignal wrote: post #2

As someone with zero knowledge regarding Zero Knowledge Proofs in a programming context, can someone give me a basic explanation regarding the utility? I do understand the basic principle of ZKP’s, but as yet I’m failing to understand how this would be applied in industry.

It is currently possible to use ZKP's to set up via a central authority a digital cash system where the bank notes are all anonymous and all transfers are anonymous. The central authority in this scenario cannot discriminate between transactions - any function that would compare two or more transactions cannot glean any useful information that would allow to discriminate. And and security of the anonymity of past tra…

[dead]

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#27

Post by jlokier »

cosignal wrote: post #2

As someone with zero knowledge regarding Zero Knowledge Proofs in a programming context, can someone give me a basic explanation regarding the utility? I do understand the basic principle of ZKP’s, but as yet I’m failing to understand how this would be applied in industry.

For me, the most powerful use of ZKPs is proof of the output of general purpose computations of any kind.

You can run an arbitrarily large, arbitrary long program, and whatever the program outputs, you can make a tiny proof-signature that says "this is the output you'll get if you run this program yourself".

The proof-signatures are relatively small, and you can verify them on small devices in milliseconds.

Another computer can trust the claimed output without having to run the program itself, by verifying the proof-signature.

This scales to arbitrarily large computations, so for example if a supercomputer says "I ran a quadrillion petaflops of your program for 1 year, and the result was the picture attached to this signature", you actually can verify that the picture is correct, quickly and efficiently - without having to trust the supplier.

It's as good as if you re-ran the program yourself (up to cryptography-grade probabilities, which is good enough).

Or if the big computer says "this entire Debian distribution of binary files was indeed compiled with this version of GCC", you can quickly verify that all the binaries are exactly what they should be - without having to trust anyone.

The proof process is rather slow, but it has gotten a lot faster over the last few years, and will continue to.

I was amazed when I learned that it's possible to securely check an arbitrarily large computation's output or result without running it yourself.

It was so counter to my intuition: it seemed like you would have to trust whoever makes the claim, or run it yourself. But you don't!

(So amazed and intrigued that I had to learn how it's done, and now part of my work these days is optimising the proof process.)

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#28

Post by shriphani »

cosignal wrote: post #2

As someone with zero knowledge regarding Zero Knowledge Proofs in a programming context, can someone give me a basic explanation regarding the utility? I do understand the basic principle of ZKP’s, but as yet I’m failing to understand how this would be applied in industry.

Examples of things you can do with ZKPs:

- Anonymous credentials (this is what Signal does) - maintain an encrypted blob representing a group chat (members list etc all stay encrypted and Signal cannot tell who is in a group chat). A normal client can provide a zkp that they are in a particular group chat (the decrypted blob contains this member for example) and have a message delivered to other group members. Both the client and the recipient can keep their identities encrypted and the zkp proves the membership of the plaintext client / recipient.

- Encrypt some metadata of a message sent to someone. You can build a ZKP that the plaintext behind the encrypted metadata satsifies some properties such as recipient is not in some blacklist (and so on). All this can be done by maintaining privacy because the metadata stays encrypted.

- Given an electronic medical record, you can prove that the record contains a vaccine without sending the record over the wire to some other party.

Lots more such ideas exist.

zkVMs are a good place to start playing with things.

Re: Programming Zero Knowledge Proofs: From Zero to Hero

#29

Post by rtpg »

shriphani wrote: post #28
cosignal wrote: post #2

As someone with zero knowledge regarding Zero Knowledge Proofs in a programming context, can someone give me a basic explanation regarding the utility? I do understand the basic principle of ZKP’s, but as yet I’m failing to understand how this would be applied in industry.

Examples of things you can do with ZKPs: - Anonymous credentials (this is what Signal does) - maintain an encrypted blob representing a group chat (members list etc all stay encrypted and Signal cannot tell who is in a group chat). A normal client can provide a zkp that they are in a particular group chat (the decrypted blob contains this member for example) and have a message delivered to other group members. Both t…

in your first example, how does Signal route messages in that model?
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