An open source zero-trust way to shuffle a deck of cards. Allowing players to have certifiable knowledge of fairness for gameplay online.

Usage

npm install zero-trust-shuffle

or with yarn:

yarn add zero-trust-shuffle

You'll need to a polygon wallet that can pay for the gas (Each call is around 250k gas), you'll also need some Link (non-bridged). All in all each call comes out a few cents.

In order to acquire non-bridged LINK on polygon you'll need to take your bridged LINK here and swap it: PegSwap Bridged Link to Unbridged

Once you have your funded wallet, here's how you might use zero-trust-shuffle:

import { zeroTrustShuffle } from "zero-trust-shuffle";

const FUNDED_WALLET_PRIVATE_KEY = "0x...";

const exampleUsage = async () => {
    const { gameStartReveal, gameEndReveal, shuffledDeck } =
        await zeroTrustShuffle({ privateKey: FUNDED_WALLET_PRIVATE_KEY });

    // On game start reveal non-secret information to clients
    sendClients(gameStartReveal);

    // Play card based game
    playPoker(shuffledDeck);

    // On game end reveal game secrets to clients
    sendClients(gameEndReveal);
};

Passing your key is only needed in the first call to zeroTrustShuffle(). Any further calls will reuse that key:

// Subsequent deck shuffle
const { gameStartReveal, gameEndReveal, shuffledDeck } =
    await zeroTrustShuffle();

VRF Polygon Contracts

Contracts are deployed on Polygon for VRF functionality. Feel free to use these. To invoke them, call transferAndCall on the Link token contract with 0.001 Link.

Mumbai Testnet -> 0x1AC8A22D9EF30069f15942451B6291de550B267F Mumbai has since been deprecated, please use mainnet contract
Polygon Mainnet -> 0x14178335e9323F92dcA7C48cf64Bab835d2AC8EC