Back to HomeDeployer Cyrus Adkisson(0xcf684d...ad1bac) Deployment Block 177,563 Deployment Date Sep 2, 2015, 09:26 PM Code Size 2.5 KB Gas at Deploy 731,528
Deployed September 2, 2015 (11 years ago)Block 177,563
A coin flip wager contract endowed with 6 ETH, deployed 2 September 2015.
Frontier EraVerified Source
Historical Significance
Randomness is the problem gambling contracts exist to expose. Every value available inside the EVM is either known in advance or chosen by the account producing the block, so a payout decided from block data can be steered by whoever mines it. This run of revisions is that lesson being learned in public, one deployment at a time, and the answer the ecosystem eventually reached, an oracle or a commit and reveal, is not available here at all.
Context
Deployed a month after the Frontier launch, when block difficulty and coinbase were still being used as randomness sources.
Key Facts
Transactions by Year
20154
Deployment Transaction: 0xe93da0e09334627d...dc376549fda113f0
Description
The player calls betAndFlip with a wager attached. The contract derives a pseudorandom value by hashing block difficulty, the coinbase address, the timestamp and the wager, then pays double on a win and keeps the stake on a loss. It refuses any wager above the uint128 limit and any wager the balance cannot cover at two to one, returning the money in both cases. Three read-only calls report the result of the last flip, the player gain or loss on it, and the endowment still held. A kill function let the creator withdraw and destroy the contract, and it was used: the address holds no code today, so this source is matched against the bytecode as it was archived at deployment. Deployed by Cyrus Adkisson from 0xcf684dfb8304729355b58315e8019b1aa2ad1bac with 6 ether as the house bankroll.
Source Verified
Historian Categories
Lottery / Gambling
Heuristic Analysis
The following characteristics were detected through bytecode analysis and may not be accurate.
Detected Type: Lottery / Gambling
Frontier Era
The initial release of Ethereum. A bare-bones implementation for technical users.
Block span: 0 — 1,149,999
July 30, 2015 — March 14, 2016
Bytecode Overview
Opcodes2,591
Unique Opcodes148
Jump Instructions123
Storage Operations47
Verified Source Available
Source verified through compiler archaeology and exact bytecode matching.
View Verification ProofShow source code (Solidity)
// Submitted by EthereumHistory (ethereumhistory.com)
contract CoinFlipper {
address creator;
uint contract_creation_value; // original endowment
uint lastmaxpayoutpossible;
int lastgainloss;
string lastresult;
function CoinFlipper() public
{
creator = msg.sender; // msg is a global variable
contract_creation_value = msg.value; // the endowment of this contract in wei
lastmaxpayoutpossible = 0;
lastresult = "no wagers yet";
lastgainloss = 0;
}
function getContractCreationValue() constant returns (uint) // returns the original endowment of the contract
{ // set at creation time with "value: <someweivalue>"
return contract_creation_value; // this is now the "balance" of the contract
}
function getEndowmentBalance() constant returns (uint)
{
return this.balance;
}
function sha(uint128 wager) constant private returns(uint256)
{
return uint256(sha3(block.difficulty, block.coinbase, now, wager)); // DISCLAIMER: I don't know if this is random enough.
}
function betAndFlip() public
{
lastmaxpayoutpossible = this.balance * 2;
if(msg.value > 340282366920938463463374607431768211455) // this number is 2^128 - 1 = uint128 limit
{
// if too large, return wager
lastresult = "wager too large";
lastgainloss = 0;
msg.sender.send(msg.value);
return;
}
else if(msg.value > lastmaxpayoutpossible) // contract has to have 2x funds to be able to pay out.
{
lastresult = "wager larger than contract's ability to pay";
lastgainloss = 0;
msg.sender.send(msg.value);
return;
}
else if (msg.value == 0)
{
lastresult = "wager was zero";
lastgainloss = 0;
// nothing wagered, nothing returned
return;
}
uint128 wager = uint128(msg.value); // limiting to uint128 guarantees that conversion to int256 will stay positive
uint hash = sha(wager);
if( hash % 2 == 0 )
{
lastgainloss = int(wager) * -1;
lastresult = "loss";
// they lost. Return nothing.
return;
}
else
{
lastgainloss = wager;
lastresult = "win";
msg.sender.send(wager * 2);
}
}
function getLastMaxPayoutPossible() constant returns (uint)
{
return lastmaxpayoutpossible;
}
function getResultOfLastFlip() constant returns (string)
{
return lastresult;
}
function getPlayerGainLossOnLastFlip() constant returns (int)
{
return lastgainloss;
}
/**********
Standard kill() function to recover funds
**********/
function kill()
{
if (msg.sender == creator)
{
suicide(creator); // kills this contract and sends remaining funds back to creator
}
}
}
/*
var coinflipperContract = web3.eth.contract([{
"constant": true,
"inputs": [],
"name": "getPlayerGainLossOnLastFlip",
"outputs": [{
"name": "",
"type": "int256"
}],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "betAndFlip",
"outputs": [],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "kill",
"outputs": [],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getEndowmentBalance",
"outputs": [{
"name": "",
"type": "uint256"
}],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getContractCreationValue",
"outputs": [{
"name": "",
"type": "uint256"
}],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getResultOfLastFlip",
"outputs": [{
"name": "",
"type": "string"
}],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getLastMaxPayoutPossible",
"outputs": [{
"name": "",
"type": "uint256"
}],
"type": "function"
}, {
"inputs": [],
"type": "constructor"
}]);
var coinflipper = coinflipperContract.new({
from: web3.eth.accounts[0],
data: '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',
gas: 1000000,
value: 6000000000000000000 /// ENDOW WITH 6 ETHER
}, function(e, contract) {
if (typeof contract.address != 'undefined') {
console.log(e, contract);
console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
}
});
> coinflipper.getEndowmentBalance();
6000000000000000000
> coinflipper.betAndFlip.sendTransaction({from:eth.coinbase, value: 1000000000000000000}); // 1 ETH. Let's see what happens
"0xc78a24881c7f70d25a817dcfcdce3347ca0cd265b7ba30a60df61e5639482bcf"
> coinflipper.getResultOfLastFlip();
"no wagers yet"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet?
"no wagers yet"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet?
"no wagers yet"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet? I'm waiting...
"no wagers yet"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet? I'm waiting...
"win"
> coinflipper.getPlayerGainLossOnLastFlip();
1000000000000000000
> web3.fromWei(coinflipper.getPlayerGainLossOnLastFlip());
1
> coinflipper.getEndowmentBalance();
5000000000000000000
> coinflipper.betAndFlip.sendTransaction({from:eth.coinbase, value: 3000000000000000000}); // 3 ETH. Let's see what happens
"0xcae272652649e07c343674d15b40a086c559408d9c66d8022de3f54932bf3d9f"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet? I'm waiting...
"loss"
> coinflipper.getEndowmentBalance();
8000000000000000000
> web3.fromWei(coinflipper.getPlayerGainLossOnLastFlip());
-3
> web3.eth.getBalance(eth.coinbase);
1806931309200681965
> web3.fromWei(web3.eth.getBalance(eth.coinbase));
1.806931309200681965
> coinflipper.betAndFlip.sendTransaction({from:eth.coinbase, value: 1500000000000000000}); // 1.5 ETH. Let's see what happens
"0xc99add577b3180ca58b1a8219f2cd282f6b77edb63e1e384b05abc434753b1a1"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet? I'm waiting...
"win"
> web3.fromWei(web3.eth.getBalance(eth.coinbase));
3.304471659200681965
> web3.fromWei(web3.eth.getBalance(eth.coinbase));
> coinflipper.kill.sendTransaction({from:eth.coinbase});
"0xed9f9e49cca76965ba32acce2b2f0b17ada467e52d55b803c26cc7132ba108fa"
*/External Links
Related contracts
GetBalance
Same deployerCyrus Adkisson experimental getter (Sep 2015) exposing the ether balance of a hardcoded address via getMyBalance(). Verified byte-for-byte with soljson v0.1.1.
0x759ad4...239a87August 26, 2015Contract 0xddcd64...a08e7b
Same deployerThe greeter tutorial contract: it stores a greeting set at deployment and can be shut down by its owner.
0xddcd64...a08e7bAugust 26, 2015basicInfoGetter
Same deployerA tour of the EVM globals, carrying the constructor of the file it was copied from
0xad826c...d33547August 31, 2015Contract 0x3ea0db...b922e0
Same deployerThe basic info getter from the solidity-baby-steps tutorials, a read only window onto the block and message globals.
0x3ea0db...b922e0August 31, 2015Contract 0xba575c...78733f
Same deployerA contract built to probe what the msg globals actually return, endowed with 5 ETH, deployed 1 September 2015.
0xba575c...78733fSeptember 1, 2015Contract 0x8b180c...c084df
Same deployerA third deployment of the msgExaminer that records its own creation message
0x8b180c...c084dfSeptember 1, 2015