A quick look at zero-knowledge proofs (bernsteinbear.com)
46 points by evakhoury 2 days ago
Cider9986 8 minutes ago
Zcash make a significant contro to ZKPs though, what would be the state without their tec?
Did their advancements have any other implications besides cryptocurrency?
jackb4040 41 minutes ago
I don't think ZKPs / programmable cryptography are useless like some of the other commenters. But I do remember being surprised, based on the way that people talk about building on top of it, to learn that the performance is so bad (except on dedicated servers) that it's basically a theoretical technology until that's fixed. Has this changed recently? Not a rhetorical question.
schoen 10 minutes ago
There's a big asymmetry where creating a proof is usually dramatically more expensive than verifying it (which is often extremely cheap!). That might be OK for some applications but still rule out other applications.
_alphageek 2 hours ago
Amazing article. Will save to explain ZKP to others.
One tiny correction
random.randrange(100) gives 300 possible commitments(3 colors for hundred nonces) After seeing a couple of revealed edges, the verifier can figure out the palette and brute-force all 300 combinations, effectively opening every commitment.
It can be mitigated if we use 128 bits of randomness, e.g. secrets.token_bytes(16).
Also I would use sha256 instead of hash. Python hash is not considered secure as it does not have proper collision resistance.
diamondclouds 2 hours ago
Not one mention that ZKP depends on servers trusting clients.
The single reason ZKP is not viable for most security is that it relies on you trusting the client to send you true information about data.
With conventional security the user sends their inputs and the server validates it.
Something I notice that is almost never mentioned when people bring up ZKP - it is pretty much only for peer-to-peer when there is no authoritative server. Or when that server trusts the “nodes” (clients).
teravor an hour ago
> relies on you trusting the client to send you true information about data
ZKP's are not magic, you need a cryptographic operation on which to operate the ZKP. this way you can conceal the input while still proving something about it. this works because the ZKP follows the trace of execution through the cryptographic primitive which proves it was executed properly and then the output was validated by some public measure.
conversely, if ZKP's ever get fast enough to be useful for this you can prove a public input (ex. source code) was compiled properly into a public output (ex. binary). for obvious reasons doing this only makes sense when it's efficient otherwise you can just execute it yourself.
diamondclouds 15 minutes ago
> the client is constrained to send you true information
Yeah ok bud. You wouldn’t last a week.
Ar-Curunir 9 minutes ago
[delayed]
goldthreads 2 hours ago
ZKP is 100% bullshit.
It’s a new word invented by people who don’t know hashing and databases already exist.
nojokepoke an hour ago
PAKE has been using ZKPs for a decade. Here. Read this : https://en.wikipedia.org/wiki/Password_Authenticated_Key_Exc...
Funny that not only are you ignorant you are violently confident in your ignorance. I suffer from this sometimes too so I get it. Get some help.
diamondclouds an hour ago
> Alice sends out
It relies on trusting that Alice’s request is valid. If Alice sends another proof, she will have a different balance. Alice decides what to send. The server blindly accepts it.
You actually don’t want that for a lot of security and that’s why nobody uses ZKP for passwords or really anywhere outside theory - dumb theory that doesn’t understand basic web dev. We already have hashing and databases. There is a narrow use case for trusting clients - like receiving updates from intranet or p2p devices - maybe you use ZKP to omit unnecessary pii. But that’s it. It’s not what you think it is.
Groxx an hour ago
nojokepoke 38 minutes ago
diamondclouds 2 hours ago
It has a use case in peer-to-peer or anywhere that you want the server to trust the connections.
Sometimes you want clients to be authoritative (although rare).
Retr0id 2 hours ago
A great way to announce that you don't understand ZKP
goldthreads 2 hours ago
Explain why you need ZKP for their flagship problem - the “prove you’re 21” thing.
Or choose any case you like.
Explain why I can’t do it without this hilariously elementary philosophy detached from real world dev.
No cheating! I get access to the same resources. Explain why I need ZKP.
striking 2 hours ago
Retr0id 2 hours ago
Ar-Curunir 8 minutes ago
[delayed]