Provably Fair Dice (Next.js Edition)

A modern, provably fair dice game demo built with Next.js, Tailwind CSS, and TypeScript.

Demo: https://provably-fair-dice.vercel.app/

Features

• Provably Fair: Verify every roll with client seeds and server hashes.
• Modern UI: Clean, responsive design using Tailwind CSS.
• Fast: Built on Next.js App Router.

Getting Started

1. Install Dependencies

   pnpm install

2. Run Development Server

   pnpm dev

   Open http://localhost:3000.

3. Run Tests

   pnpm test

4. Build for Production

   pnpm build
   pnpm start

Verification

Each roll is generated using the following logic:

1. Seed String: clientSeed + '_' + serverSeed + '_' + nonce
2. Hash: SHA256(seedString)
3. Result: parseInt(hash.substring(0, 10), 16) % 10001

The result is a number between 0 and 10,000. If it's below the target, you win.

You can verify any roll in the UI by clicking "Verify" in the history table, which displays all inputs and the calculation breakdown.

House Edge Math

The house edge is baked into the win chance calculation:

winChance = 99 / multiplier
target = winChance * 100

For example, at a 2x multiplier:

• winChance = 99 / 2 = 49.5%
• target = 4950
• Expected Value = 49.5% * 2x = 99%
• House Edge = 1%

The player must roll under 4950 (out of 10001) to win, which gives a 49.5% chance. The 1% edge comes from the fact that a "fair" 2x would require 50%, but we cap at 99% of that.

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Productionization Checklist

⚠️ DISCLAIMER: This project is for educational purposes only. Operating an unlicensed gambling platform is illegal in most jurisdictions. Do not use this code for real-money gambling without proper legal licensing and compliance.

If you were to build a real provably fair system, you would need to implement:

• Crypto Deposits: Integrate with a blockchain (e.g., Bitcoin, Ethereum, Solana) for deposit addresses and confirmation monitoring.
• Server Seed Hash Chaining: Pre-generate a chain of server seeds and reveal only the hash upfront. Each bet reveals the previous seed.
• Seed Rotation on Reveal: When a client requests to reveal their server seed, rotate to a new one and require them to set a new client seed.
• Ledger Based on Crypto Confirmation: Only credit bets after a configurable number of blockchain confirmations.
• Payouts & Batching: Implement withdrawal queues with batched transactions to reduce fees.