Questions tagged [schnorr-identification]

The Schnorr Identification Protocol relies upon the security of the Discrete Logarithm Problem. Schnorr's protocol was introduced after, and is comparable to, the identification protocol of Fiat and Shamir and that of Guillou-Quisquater.

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Schnorr protocol is witness-hiding?

Regular 3-steps Schnorr protocol is a proof of knowledge system for discrete logarithm. It's honest-verifier zero-knowledge, but not full zero-knowledge. My question is, is it witness-hiding? (I guess ...
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Could Diffie-Hellman protocol serve as a zero-knowledge proof of knowledge of discrete logarithm?

The Schnorr identification protocol is widely recognized as the simplest ZKPoK of the discrete logarithm (more clearly, Honest-Verifier ZKPoK). However, I can't figure out why this simple protocol, ...
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Could any one suggest alternative Zero knowledge proof protocol to Schnorr protocol ZKP?

I read that Schnorr protocol cannot be proved zero knowledge on that link: Perfect zero knowledge for the Schnorr protocol? Could any one suggest alternative Zero knowledge proof protocol so a prover ...
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139 views

How to make the interactive Schnorr identification protocol become non-interactive

I am reading about ZKP and I found this interesting question about changing this protocol from interactive Schnorr identification protocol to non-interactive and I need help in solving it : Peggy (...
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Sigma protocol for AND-composition involving the same secret

Say we have two public cyclic groups $G_1$, $G_2$ of corresponding prime orders $p_1$, $p_2$, and known generators $g_1$, $g_2$. Say $g_3$ is also a generator of $G_2$. For publicly known $C_1$ and $...
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What is difference between an identification scheme and a digital signature scheme?

It seems we can use every identification scheme to sign and verify a message and vice versa. I am right or not? What is difference between an identification scheme and a digital signature scheme?
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377 views

Schnorr signature using discrete logarithm / problem with python implementation [closed]

For educational purposes (by purpose with small values for the prime order q), I tried to write a small Python implementation of the Schnorr signature described in the Wikipedia article https://en....
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Schnorr identification protocol security proof

I read about security proof of Schnorr identification protocol against impersonation attack. For the sake of comprehensibility let me sum up the protocol: Given group $G$ with generator $g$. Verifier ...
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The danger of Hash collision in Schnorr NIZK

We use Fiat–Shamir heuristic to turn Schnorr ZK to NIZK. So now NIZK is secure against chosen message attacks in the random oracle model, that is, ideal hash function: every unique query leads to a ...
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Schnorr identification scheme without changing k flaws

The Schnorr identification scheme is being used to remotely log into a home computer which has stored $p$, $α$ and $β(\equiv α^a(mod p))$ - with $a$ the password. This works thusly: 1) The user ...
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1answer
174 views

Understanding the definition of Schnorrs identification protocol

I have some trouble in understanding the definition of Schnorr's Identification protocol. The is the definition that I received: Prover and verifier agree on a cyclic group $G$ of prime order $q$ ...
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212 views

Plausible Deniability in Schnorr

How does a dishonest verifier affect plausible deniability of the interactive Schnorr protocol?
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Security proof of partially blind signature (schnorr signature based)

I read a representative paper about partially blind signature. Abe and Okamoto - "provably secure partially blind signature". They suggested a partially blind signature scheme based on Schnorr ...
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757 views

Schnorr protocol: how does malicious verifier win?

My question is about the challenge space size in Schnorr protocol. To be precise, I feel I've read all the Internet (twice) and I still don't understand why is it bad to allow challenge space to be ...
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81 views

How we can create a protocol using Schnorr as identification scheme and a hash function as a puzzle?

My question has to do with the creation of a PoWorK( Proof of Work or Knowledge) protocol.How we can create a protocol like this ,using Schnorr as the underlying CVZK protocol and using a hash ...
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261 views

Schnorr's identication protocol

Schnorr's identification protocol is said to be a honest verifier zero knowledge protocol. Does it imply it will not work if the verifier is dishonest? I'm wondering if this is the case, it would ...
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1answer
488 views

Schnorr Identification protocol sometimes wrong?

I'm implementing the Schnorr Identification protocol as part of a larger protocol. In a large percentage of cases, around 20%, my test fails. I don't think it's a code problem, although possible, but ...
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972 views

Schnorr Identification Scheme under active adversary

According to the paper “GQ and Schnorr Identification Schemes: Proofs of Security against Impersonation under Active and Concurrent Attacks” by Mihir Bellare and Adriana Palacio, the Schnorr ...
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How to forge Schnorr signatures if you can guess the challenge

Underlying the Schnorr signature is an identification protocol: let $G$ be a cyclic group where discrete log is "hard" and choose $g$ as a generator of $G$. Now have Alice pick a random (secret) ...