ZKit - Circom Zero Knowledge Kit

A zero knowledge kit that helps you interact with Circom circuits.

• Generate and verify ZK proofs with a single line of code.
• Render optimized Solidity | Vyper verifiers.
• Build and work with ZK witnesses.

Installation

To install the package, run:

npm install --save-dev @solarity/zkit

Usage

Important

The kit is not meant to be used directly as its fitness relies heavily on the environment, Circom compilation artifacts management, processing of remappings, etc. Consider using hardhat-zkit which is a complete, developer-friendly package.

CircuitZKit

CircuitZKit is a user-friendly interface for interacting with circom circuits.

To create a CircuitZKit object it is necessary to pass a config:

CircuitZKitConfig = {
  circuitName: string;
  circuitArtifactsPath: string;
  verifierDirPath: string;
  provingSystem?: VerifierProvingSystem;
};

This config contains all the information required to work with the circuit, namely:

• circuitName - Name of the circuit file without extension
• circuitArtifactsPath - Full path to compilation artifacts for the desired circuit
• verifierDirPath - Full path to the directory where Solidity | Vyper verifier file will be generated
• provingSystem - The proving system that will be used to generate the verifier contract. Right now only groth16 is supported

getTemplate()

Static CircuitZKit function that returns the contents of a template file by the passed type.

const templateContent = CircuitZKit.getTemplate("groth16", "sol");

createVerifier()

Creates a Solidity | Vyper verifier contract on verifierDirPath path, which was specified in the config.

await multiplier.createVerifier("sol");

calculateWitness()

Calculates a witness in the tmp directory and returns its json representation.

/// witness = [1n, 200n, 20n, 10n]
const witness = await multiplier.calculateWitness({ a: 10, b: 20 });

generateProof()

Generates a proof for the given inputs.

/// { proof: { pi_a, pi_b, pi_c, protocol, curve }, publicSignals: [6] }
const proof = await multiplier.generateProof({ a: 2, b: 3 });

verifyProof()

Verifies the proof.

/// true
const isValidProof = await multiplier.verifyProof(proof);

generateCalldata()

Generates calldata by proof for the Solidity | Vyper verifier's verifyProof() method.

/// You can use this calldata to call the verifier contract
const calldata = await multiplier.generateCalldata(proof);

Known limitations

• Currently, ZKit supports only the Groth16 proving system.