ZoKrates/zokrates_js

zokrates.js

JavaScript bindings for ZoKrates project.

npm install zokrates-js

Importing

Bundlers

Note: As this library uses a model where the wasm module itself is natively an ES module, you will need a bundler of some form. Currently the only known bundler known to be fully compatible with zokrates-js is Webpack. The choice of this default was done to reflect the trends of the JS ecosystem.

import { initialize } from 'zokrates-js';

Node

const { initialize } = require('zokrates-js/node');

Example

function importResolver(currentLocation, importLocation) {
  console.log(currentLocation + ' is importing ' + importLocation);
  // implement your resolving logic here
  return {
    source: "def main() -> (): return",
    location: importLocation
  };
}

initialize().then((zokratesProvider) => {
    const source = "def main(private field a) -> (field): return a * a";

    // compilation
    const artifacts = zokratesProvider.compile(source, "main", importResolver);

    // computation
    const { witness, output } = zokratesProvider.computeWitness(artifacts, ["2"]);

    // run setup
    const keypair = zokratesProvider.setup(artifacts.program);

    // generate proof
    const proof = zokratesProvider.generateProof(artifacts.program, witness, keypair.pk);

    // export solidity verifier
    const verifier = zokratesProvider.exportSolidityVerifier(keypair.vk, "v1");
});

API

initialize()

Loads binding wasm module and returns a promise with ZoKrates provider.

Returns: Promise<ZoKratesProvider>

compile(source, location, resolveCallback[, config])

Compiles source code into ZoKrates internal representation of arithmetic circuits.

Parameters:

• source - Source code to compile
• location - Root location of the module which is being compiled
• resolveCallback - User-defined callback used to resolve imports
• config - Compilation config

Returns: CompilationArtifacts

computeWitness(artifacts, args)

Computes a valid assignment of the variables, which include the results of the computation.

Parameters:

• artifacts - Compilation artifacts
• args - Array of arguments (eg. ["1", "2", true])

Returns: ComputationResult

setup(program)

Generates a trusted setup for the compiled program.

Parameters:

• program - Compiled program

Returns: SetupKeypair

exportSolidityVerifier(verificationKey, abi)

Generates a Solidity contract which contains the generated verification key and a public function to verify a solution to the compiled program.

Parameters:

• verificationKey - Verification key from the setup keypair
• abi - Abi version ("v1" | "v2")

Returns: string

generateProof(program, witness, provingKey)

Generates a proof for a computation of the compiled program.

Parameters:

• program - Compiled program
• witness - Witness (valid assignment of the variables)
• provingKey - Proving key from the setup keypair

Returns: Proof