Provably fair

Game result

// Code written in javascript
const clientSeed = '';
const serverSeed = '';
const nonce = 0;

const crypto = require('crypto');

function hmacSha256(key, message) {
  return crypto.createHmac('sha256', Buffer.from(key, 'hex'))
    .update(message)
    .digest('hex');
}

function roll(serverSeed, clientSeed, nonce) {
  const hash = hmacSha256(serverSeed, `${clientSeed}:${nonce}`);
  const RANGE = 10001;
  const MAX = 0xffffffff;
  const FAIR = MAX - (MAX % RANGE);
  for (let i = 0; i + 8 <= hash.length; i += 8) {
    const value = parseInt(hash.slice(i, i + 8), 16);
    if (value < FAIR) return (value % RANGE) / 100;
  }
}

console.log(roll(serverSeed, clientSeed, nonce)); // 0.00 - 100.00