Crate sigma_proofs 

Σ-rs: Sigma Protocols in Rust

Σ-rs is a Rust library for constructing zero-knowledge proofs using Sigma protocols (Σ-protocols). It allows proving knowledge of secret data without revealing the data itself.

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What are Sigma Protocols?

Sigma protocols are interactive cryptographic protocols that allow a prover to convince a verifier they know a secret (like a private key) without revealing the secret itself. They follow a simple three-step pattern: commitment, challenge, response.

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Basic Usage

let mut instance = sigma_proofs::LinearRelation::new();
let mut rng = rand::thread_rng();

// Define the statement:
// Prove knowledge of (x, r) such that C = x·G + r·H (Pedersen commitment)
let [var_x, var_r] = instance.allocate_scalars();
let [var_G, var_H] = instance.allocate_elements();
instance.allocate_eq(var_G * var_x + var_H * var_r);
instance.set_elements([(var_G, RistrettoPoint::generator()), (var_H, RistrettoPoint::random(&mut rng))]);

// Assign the image of the linear map.
let witness = vec![Scalar::random(&mut rng), Scalar::random(&mut rng)];
instance.compute_image(&witness);

// Create a non-interactive argument for the instance.
let nizk = instance.into_nizk(b"your session identifier").unwrap();
let narg_string: Vec<u8> = nizk.prove_batchable(&witness, &mut rng).unwrap();
// Print the narg string.
println!("{}", hex::encode(narg_string));

The library provides building blocks for creating zero-knowledge proofs:

1. Define your mathematical relation using LinearRelation
2. Convert to non-interactive using fiat_shamir::Nizk
3. Generate and verify proofs.

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Core Components

• traits::SigmaProtocol: The fundamental three-move protocol interface
• linear_relation::LinearRelation: Express mathematical relations over groups
• fiat_shamir::Nizk: Convert interactive proofs to standalone proofs
• composition::ComposedRelation: Combine multiple proofs together

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Σ-rs is designed to be modular, extensible, and easy to integrate into different groups, protocols depending on sigma protocols, and other proof systems.

Re-exports

pub use group::msm::MultiScalarMul;

pub use linear_relation::LinearRelation;

pub use group::serialization;

Modules

composition

Protocol Composition with AND/OR Logic

errors

Error: Error Types for Zero-Knowledge Proofs.

group

linear_relation

Linear Maps and Relations Handling.

rng

The pseudo-random generator used for sampling scalars.

traits

Generic interface for 3-message Sigma protocols.

Structs

Nizk

A Fiat-Shamir transformation of a SigmaProtocol into a non-interactive proof.