SteemCrash Probably Fair Seeding Event

[fulluser]

Disclaimer: I was hired by steemcrash.com to make this seeding event and therefore set up the provably fair on the game. I will not be part of the team that will manage this site.

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

• A chain of 10 million sha256 hashes was generated, starting with a Server Secret that has been repeatedly fed the output of sha256 hash back into itself 10 million times.
  The final hash in the chain is: e68e26b9ae2090dde4be1e00af21c6d4ad271e76caa699ab8ff52f34033cb730, by publicizing it here we are preventing any ability to pick an alternate sha256 chain.
• SteemCrashwill 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 Bitcoin block that hasn't yet been mined: block 484300.

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 money pot 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 =  'If you knew this, you could steal all my money';
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 e68e26b9ae2090dde4be1e00af21c6d4ad271e76caa699ab8ff52f34033cb730. That is to say, the first game's hash played under the new provably fair scheme, when hashed will be e68e26b9ae2090dde4be1e00af21c6d4ad271e76caa699ab8ff52f34033cb730

[englishflavor]

No opinion. Quoting so this cannot be edited.

Disclaimer: I was hired by steemcrash.com to make this seeding event and therefore set up the provably fair on the game. I will not be part of the team that will manage this site.

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

• A chain of 10 million sha256 hashes was generated, starting with a Server Secret that has been repeatedly fed the output of sha256 hash back into itself 10 million times.
  The final hash in the chain is: e68e26b9ae2090dde4be1e00af21c6d4ad271e76caa699ab8ff52f34033cb730, by publicizing it here we are preventing any ability to pick an alternate sha256 chain.
• SteemCrashwill 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 Bitcoin block that hasn't yet been mined: block 484300.

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 money pot 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 =  'If you knew this, you could steal all my money';
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 e68e26b9ae2090dde4be1e00af21c6d4ad271e76caa699ab8ff52f34033cb730. That is to say, the first game's hash played under the new provably fair scheme, when hashed will be e68e26b9ae2090dde4be1e00af21c6d4ad271e76caa699ab8ff52f34033cb730