Poseidon proof

A library to generate and verify Poseidon proofs.

Originally developed for integration with Semaphore V4, this library also functions effectively as a standalone tool. Notable use cases in connection with Semaphore can be:

• allowing a Semaphore user to prove that they possess the secret value associated with the identity commitment of their Semaphore identity,
• unmasking the identity of zero-knowledge proofs earlier created using Semaphore.

The Snark artifacts (.wasm and .zkey files) can be specified or not in the generate function parameters and can possibly be downloaded using the following URLs:

• https://snark-artifacts.pse.dev/poseidon/{version}/poseidon-{numberOfInputs}.wasm
• https://snark-artifacts.pse.dev/poseidon/{version}/poseidon-{numberOfInputs}.zkey

[!WARNING]
The Snark artifacts currently used to generate zero-knowledge proofs are the result of an insecure trusted setup, and the library has not yet been audited. Therefore, it is advised not to use it in production.

🛠 Install

npm or yarn

Install the @zk-kit/poseidon-proof package:

npm i @zk-kit/poseidon-proof
Copy

or yarn:

yarn add @zk-kit/poseidon-proof
Copy

📜 Usage

import { generate, verify } from "@zk-kit/poseidon-proof"

// A public value used to contextualize the cryptographic proof and calculate the nullifier.
const scope = "scope"
// The message (preimage) to prove (secret).
const messages = [1, 2]

// Generate the proof.
const fullProof = await generate(messages, scope)

/*
    nb. scope, digest and nullifier are always the same - proof is variable.
    {
        scope: '2',
        digest: '13713635907739611880977640264956372443229506353728466835599871320028961887800',
        nullifier: '4995263610384888704435371233168916617325583088652670186865584118891394144999',
        proof: [
            '4344680442683455359115899095464919042642166233886432616638435348359080260980',
            '20569010229031596977566212621532395450352277701036306316464269899598925981651',
            '19318221594436336163085169568471746851468100277321435282188061183430353155289',
            '13863222659316400652438453097923451250965656325472339120118358727133180331649',
            '2718553541880998786976126630362604850217726344847462841516918030540821216281',
            '11960084231774590415377471656397863783771599717615252119734899677642065267169',
            '10666072962579546268534775428261696356732715643486735369393626224913301307278',
            '4251217137130113647513155953595492143724626859298741948572817563032672674599'
        ]
    }
*/
console.log(fullProof)

// If not specified, the Snark artifacts are downloaded automatically.
// You can specify them as follows.

// const fullProof = await generate(message, scope, {
//     wasm: "<your-path>/poseidon-proof.wasm",
//     zkey: "<your-path>/poseidon-proof.zkey"
// })

// Verify the proof.
const response = await verify(fullProof)

// true.
console.log(response)

// Eventually you may want to check the nullifier.
Copy

📈 Benchmarks

Benchmarks were run on an Intel Core i7-1165G7, 16 GB RAM machine (with two inputs).

import { generate, verify } from "@zk-kit/poseidon-proof"

console.time("generate")

const proof = await generate([1, 2], "scope")

console.timeEnd("generate")

console.time("verify")

console.log(await verify(proof))

console.timeEnd("verify")
Copy