0x0f76...e8c7

Lottery / Gambling

0x0f76dc3f4bb3...9527c323e8c7

FrontierContract #757Exact Bytecode MatchEdit this contract

Deployed September 3, 2015 (11 years ago)Block 178,497

A coin flip wager contract carrying a commented-out attempt at using a block hash, endowed with 1 ETH on 3 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 no contract could yet draw randomness from anything but block data.

Key Facts

Deployer

Cyrus Adkisson(0xcf684d...ad1bac)

Deployment Block

178,497

Deployment Date

Sep 3, 2015, 04:17 AM

Code Size

2.4 KB

Gas at Deploy

687,258

Transactions by Year

20152

Deployment Transaction: 0xfa5584a7558f85b5...7a08a146971e3f4f

Description

This revision keeps the wager and payout logic of the day before and adds, commented out, a first attempt to draw the outcome from a block hash instead of block difficulty and the coinbase address. The commented lines and the storage slot left behind for the hash record the attempt without using it, so the deployed behaviour is unchanged from the previous version. A kill function was used, so no code remains and the source is matched against the bytecode as archived at deployment. Deployed by Cyrus Adkisson from 0xcf684dfb8304729355b58315e8019b1aa2ad1bac.

Source Verified

Exact bytecode match(2,496 bytes)

Compiler: v0.1.1+

View verification proof

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

Opcodes2,496

Unique Opcodes139

Jump Instructions118

Storage Operations45

Verified Source Available

Source verified through compiler archaeology and exact bytecode matching.

View Verification Proof

Show source code (Solidity)

// Submitted by EthereumHistory (ethereumhistory.com)
contract CoinFlipper {

    address creator;
    uint contract_creation_value;	// original endowment
    int lastgainloss;
    string lastresult;
    uint lastblocknumberused;
   // bytes32 lastblockhashused;

    function CoinFlipper() private 
    {
        creator = msg.sender; 								// msg is a global variable
        lastresult = "no wagers yet";
        lastgainloss = 0;
    }
	
    function getEndowmentBalance() constant returns (uint)
    {
    	return this.balance;
    }
    
    function sha(uint128 wager) constant private returns(uint256)  // DISCLAIMER: This is pretty random... but not truly random.
    { 
        return uint256(sha3(block.difficulty, block.coinbase, now, wager));  
    }
    
    function betAndFlip() public               
    {
    	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 * 2) > this.balance) 			// contract has to have 2*wager funds to be able to pay out. (current balance INCLUDES the wager sent)
    	{
    		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
    	
    	lastblocknumberused = block.number;
    	//lastblockhashused = block.blockhash(block.number - 1);
    	
	   	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 getLastBlockNumberUsed() constant returns (uint)
    {
        return lastblocknumberused;
    }
    
   // function getLastBlockHashUsed() constant returns (bytes32)
  //  {
  //  	return lastblockhashused;
   // }

    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": true,
    "inputs": [],
    "name": "getLastBlockNumberUsed",
    "outputs": [{
        "name": "",
        "type": "uint256"
    }],
    "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": "getResultOfLastFlip",
    "outputs": [{
        "name": "",
        "type": "string"
    }],
    "type": "function"
}, {
    "inputs": [],
    "type": "constructor"
}]);

var coinflipper = coinflipperContract.new({
    from: web3.eth.accounts[0],
    data: '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',
    gas: 1000000,
    value: 6000000000000000000 // start with endowment of 6 ETH
}, function(e, contract) {
    if (typeof contract.address != 'undefined') {
        console.log(e, contract);
        console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
    }
});

// ********** after deployment

> 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"
  
  
 // ************** after separate deployment with smaller endowment to test payout safety limit
 
  Contract mined! address: 0xb0824b45f4a4c1ee4df356378d555c7f4366fa4c transactionHash: 0x065580a137654a816abdeb27e690e6c96f59dce92a9e8064f6f8c3c49cf0b681

> coinflipper.getEndowmentBalance();   // 1 eth
1000000000000000000
> coinflipper.betAndFlip.sendTransaction({from:eth.coinbase, value: 3000000000000000000}); // 3 ETH, more than endowment can handle. Let's see what happens
"0x66b5ae12f215d1bcf1a1656f79ccedc69612dc891f35dce5dbd6ead8854f0cb1"
> 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...
"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...
"wager larger than contract's ability to pay"
> coinflipper.getEndowmentBalance();
1000000000000000000
> coinflipper.betAndFlip.sendTransaction({from:eth.coinbase, value: 500000000000000000}); // .5 ETH.
"0x16ef5f3f0778b1252dcfd3b55f09ab97382f23d8ad7489f1f1b45d88eb7588f5"
> coinflipper.getResultOfLastFlip(); // has the tx been mined yet? I'm waiting...
"loss"
  
  
  
 */

External Links

Etherscan Verified Source (if any)

Related contracts

GetBalance

Same deployer

Cyrus 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, 2015

Contract 0xddcd64...a08e7b

Same deployer

The greeter tutorial contract: it stores a greeting set at deployment and can be shut down by its owner.

0xddcd64...a08e7bAugust 26, 2015

basicInfoGetter

Same deployer

A tour of the EVM globals, carrying the constructor of the file it was copied from

0xad826c...d33547August 31, 2015

Contract 0x3ea0db...b922e0

Same deployer

The basic info getter from the solidity-baby-steps tutorials, a read only window onto the block and message globals.

0x3ea0db...b922e0August 31, 2015

Contract 0xba575c...78733f

Same deployer

A contract built to probe what the msg globals actually return, endowed with 5 ETH, deployed 1 September 2015.

0xba575c...78733fSeptember 1, 2015

Contract 0x8b180c...c084df

Same deployer

A third deployment of the msgExaminer that records its own creation message

0x8b180c...c084dfSeptember 1, 2015