Questions tagged [fiat-shamir]

The Fiat–Shamir heuristic takes an interactive proof of knowledge and uses this as base to create a digital signature.

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Weak Challenge Generation - Fiat-Shamir Heuristic

The Fiat-Shamir heuristic may be applied to transform a Sigma-Protocol on R(x,w) into a ZKPoK. Let's call the prover's first message ...
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Why Fiat-Shamir based signatures incur a security loss?

I read here that assuming we have a Fiat-Shamir (FS) signature $\Sigma$ that is secure based on the hardness of a particular hard problem $\Pi$. Then, the security proof of $\Sigma$ in the classical ...
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Could be El-Gamal signature scheme constructed via Fiat-Shamir heuristic?

For example, Schnorr signature is pretty similar to El-Gamal. And everywhere where Schnorr signature is explained (for example - on Wikipedia), there's said that there's Schnorr scheme which is ...
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Is using Fiat-shamir Heuristic safe?

What I'd like to do is to have the Prover store a value x where x remains hidden. From x, I'...
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Sigma Protocol with Privacy-preserving Discrete Logarithms?

I've been reading up on Sigma Protocols and Fiat-Shamir Heuristic. There is a small problem I see here that is possibly already solved, but I'd like to know if it has a solution. Peggy wants to prove ...
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Need tips on how to break Fiat-Shamir sigma-protocol (programming challenge)

I'm completely stuck on an university programming challenge and I need some tips to get me out of the valley I'm in, you don't need to give the full answer if you do not wish to. What we have: Fiat ...
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Valid reencryption of simple mixnet

How can I provide a non interactive proof using the Fiat Shamir method for the valid reencryption of a simple mixnet?
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Fiat Shamir with S^3

I'm trying to do Fiat Shamir but with $I = S^3 \pmod n$ where $S$ is the secret key. How will I prove that I know the cube root? I tried doing the old formula but with instead with $(RS)^3 = x*I \pmod ...
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Zero Knowledge Non Interactive Proof with random oracle

I am trying to write an assay about Non Interactive Zero-Knowledge proofs and would like to take the simple discrete logarithm problem example fallowing the Feige-Fiat-Shamir heuristics. I understand ...
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Why in the Fiat-Shamir heuristc for proving the knowledge of a discrete logarithm an hard to invert function has to be used to create the challenge?

Consider this example from Camenisch, J., & Stadler, M. (1997). Proof systems for general statements about discrete logarithms. Technical Report/ETH Zurich, Department of Computer Science, 260.. ...