zkkit proof

Generate a zero-knowledge proof from witness and proving key

Description

The proof command wraps snarkjs groth16 prove to generate a zero-knowledge proof. snarkjs performs the cryptographic operations using the witness and proving key.

Under the hood: This command runs snarkjs groth16 prove circuit_0000.zkey outputs/[witness] [proof] [public]

Usage

bash

zkkit proof [circuit-name]

Options

--witnessPath to witness file (default: witness.wtns)
--zkeyPath to proving key file
-o, --outputOutput file path (default: proof.json)

Examples

Generate proof for a circuit:

bash

zkkit proof multiplier

Specify custom witness and output files:

bash

zkkit proof multiplier --witness custom_witness.wtns -o my_proof.json

Output

This command generates two files:

proof.json - The zero-knowledge proof
public.json - Public signals/inputs

Implementation

View how this command works under the hood:

src/commands/proof.js

import { run } from "../utils/exec.js";

export default async function proof(opts = {}) {
  const {
    witness = "witness.wtns",
    proof = "proof.json",
    output = "public.json",
  } = opts;

  await run(
    `snarkjs groth16 prove circuit_0000.zkey outputs/${witness} ${proof} ${output}`
  );

  console.log("✔ Proof generated: proof.json, public.json");
}

What it does:

Accepts witness filename (defaults to witness.wtns)
Accepts proof output filename (defaults to proof.json)
Accepts public signals filename (defaults to public.json)
Uses Groth16 protocol to generate zero-knowledge proof from witness and proving key
Outputs both the proof and public inputs/outputs as separate JSON files
The proof is succinct and can be verified quickly without revealing private inputs