Welcome to the EthChase.io Provably Fair Seeding Event!
EthChase is a licensed clone of the popular bitcoin game Bustabit, and is played with Ethereum.
This will reuse the idea posted by Ryan and used for Bustabit v1.
The reference code (javascript) is as follows:
The method to create the hash chain is simply sha256:
The method to convert a game hash, mix it with the picked client seed to a money pot multiplier:
The chain could be generated with code such as:
Using our chosen starting serverSeed, the hash terminating the chain is 6b811a0f7816f610564cd3738ad72e5007bd6161efaaac4ac5a6dd316a0cbaa8. That is to say, the first game's hash played under the new provably fair scheme, when hashed will be 6b811a0f7816f610564cd3738ad72e5007bd6161efaaac4ac5a6dd316a0cbaa8.
EthChase is a licensed clone of the popular bitcoin game Bustabit, and is played with Ethereum.
This will reuse the idea posted by Ryan and used for Bustabit v1.
- A chain of 10 million (1e7) 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: 6b811a0f7816f610564cd3738ad72e5007bd6161efaaac4ac5a6dd316a0cbaa8, by publicizing it here we are preventing any ability to pick an alternate sha256 chain. - EthChase.io 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 an Ethereum block that hasn't yet been mined: block 6200000
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');
}
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));
}
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 terminating hash is: ', terminatingHash);
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 terminating hash is: ', terminatingHash);
Using our chosen starting serverSeed, the hash terminating the chain is 6b811a0f7816f610564cd3738ad72e5007bd6161efaaac4ac5a6dd316a0cbaa8. That is to say, the first game's hash played under the new provably fair scheme, when hashed will be 6b811a0f7816f610564cd3738ad72e5007bd6161efaaac4ac5a6dd316a0cbaa8.
Looks good 👍
Quoting for reference. Also, I confirm that Ethereum block 6200000 has not been mined yet and the current block is 6192588 at the time of this writing.