Title: SteemCrash Probably Fair Seeding Event
Post by: fulluser on September 09, 2017, 02:28:57 AM
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 (https://bitcointalk.org/index.php?topic=922898.0). - 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: 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: 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: 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
Title: Re: SteemCrash Probably Fair Seeding Event
Post by: englishflavor on September 09, 2017, 02:39:25 AM
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 (https://bitcointalk.org/index.php?topic=922898.0). - 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: 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: 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: 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
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