Latest posts of: nons

Quote from: FluxTube on February 01, 2018, 10:15:13 AM

Please notice: litecoin.win is formerly known as ltcrash.com and bustacoin.com. See https://bitcointalk.org/index.php?topic=2782356

This will reuse the idea posted by Ryan and used for Bustabit.

This is an event to prove litecoin.win is fair.

Starting with a secret seed I've generated a chain of 10,000,000 SHA256 hashes. Each element is the hash of the lowercase, hexadecimal string representation of the previous hash. The hash of the chain's last element is: 281baeeb0f2dc9c9a0875b7362483a50dfd7e37a33a75d82ed9aed82bcb53544
litecoin.win will play through that chain of hashes, in reverse order, and use the hashes to determine the crash point.
To avoid criticism that the Server Secret used in step 1 was carefully chosen to generate lots of "bad" crash points, each hash in the chain will be salted with a client seed, which we have no control of.
The client seed will be the block hash of a Litecoin block that hasn't yet been mined: block 507084

The reference code (javascript) is as follows:

The method to create the hash chain is simply sha256:

Code:

function genGameHash(serverSeed) {
  return crypto.createHash('sha256').update(serverSeed).digest('hex');
}

The method to convert a game hash, mix it with the picked client seed to a litecoin.win multiplier:

Code:

function crashPointFromHash(serverSeed, clientSeed) {
  function divisible(hash, mod) {
    // We will read in 4 hex at a time, but the first chunk might be a bit smaller
    // So ABCDEFGHIJ should be chunked like  AB CDEF GHIJ
    var val = 0;
    
    var o = hash.length % 4; 
    for (var i = o > 0 ? o - 4 : 0; i < hash.length; i += 4) {
      val = ((val << 16) + parseInt(hash.substring(i, i+4), 16)) % mod;
    }

    return val === 0;
  }

  var hash = crypto.createHmac('sha256', serverSeed).update(clientSeed).digest('hex');

  /* In 1 of 101 games the game crashes instantly. */
  if (divisible(hash, 101))
     return 0;

  /* Use the most significant 52-bit from the hash
     to calculate the crash point */
  var h = parseInt(hash.slice(0,52/4),16);
  var e = Math.pow(2,52);

  return Math.floor((100 * e - h) / (e - h));
}

The chain could be generated with code such as:

Code:

var serverSecret =  'secret';
var clientSeed = '0000examplehash';

var gamesToGenerate = 1e7;

var serverSeed = serverSecret;

for (var game = gamesToGenerate; game > 0; --game) {
  serverSeed = genGameHash(serverSeed);
  console.log('Game ' +  game + ' has a crash point of ' + (crashPointFromHash(serverSeed, clientSeed) / 100).toFixed(2) +'x', '\t\tHash: ' + serverSeed);
}

var terminatingHash = genGameHash(serverSeed);

console.log('The final hash is: ', terminatingHash);

Using our chosen starting serverSeed, the hash terminating the chain is 281baeeb0f2dc9c9a0875b7362483a50dfd7e37a33a75d82ed9aed82bcb53544

Nice !