@zk-kit/groth16

SnarkJS Groth16

A snippet of SnarkJS code for verifying and generating Groth16 proofs only.

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This package contains SnarkJS functions for generating and verifying zero knowledge proofs with Groth16 specifically. In addition to the original code it also uses the cached bn128 curve if it already exists, making verification and generation of consecutive proofs faster.

Some advantages of using this package instead of snarkjs directly are:

• It only includes code to verify and generate Groth16 proofs, making your final bundle lighter.
• It doesn't call the ffjavascript buildBn128 function if a bn128 cached curve already exists, making verification and generation of consecutive proofs much faster (e.g. verification seems to be ~9 times faster after the first one).
• It includes TS types.
• It provides an ESM bundle that is compatible with browsers. So there is no need to add any polyfill or additional configuration.

🛠 Install

npm or yarn

Install the @zk-kit/groth16 package and its peer dependencies with npm:

npm i @zk-kit/groth16

or yarn:

yarn add @zk-kit/groth16

📜 Usage

# prove(input: CircuitSignals, wasmFile: ZKArtifact, zkeyFile: ZKArtifact): Promise<{ proof: Groth16Proof publicSignals: PublicSignals }>

import { prove } from "@zk-kit/groth16"

const input = {
    message: 12,
    scope: 122
}

const proof = await prove(input, "./circuit.zkey", "./circuit.wasm")

console.log(proof)
/*
{
    proof: {
        pi_a: [
            '8259885706934172848141475422209230656096448508815982888010519325096632035723',
            '3142099172052192611205205328157407975469005554072266974009053708782134081166',
            '1'
        ],
        pi_b: [ [Array], [Array], [Array] ],
        pi_c: [
            '13863804425308906943736719856399634046638544298517159271373916818387594277305',
            '21340646707244019956779928177502771923632450548108204371058275686712196195969',
            '1'
        ],
        protocol: 'groth16',
        curve: 'bn128'
    },
    publicSignals: [
        '527758365153958423212195330785598453331596731388181860789801455413116800554',
        '19104626566001952573667666924569656871967113105870778077087237826253896482830',
        '122'
    ]
}
*/

# verify(verificationKey: any, proof: { proof: Groth16Proof publicSignals: PublicSignals }): Promise<boolean>

import { verify } from "@zk-kit/groth16"
import verificationKey from "./circuit.json"

const response = await verify(verificationKey, proof)

console.log(response) // true

# buildBn128(): Promise<any>

import { buildBn128 } from "@zk-kit/groth16"

const curve = await buildBn128() // WasmField1
// https://github.com/iden3/ffjavascript/blob/master/src/wasm_field1.js