EtherLotto

Ethereum blockchain based lottery.

Playing

If you want to play to this lottery game invoked play method sending 10 weis to the following smart contract:

0xa11e4ed59dc94e69612f3111942626ed513cb172

If you are the lucky winner then all the jackpot will be sent to your account.

Smart contract ABI

[{
    constant: true,
    inputs: [],
    name: "pot",
    outputs: [{
        name: "",
        type: "uint256"
    }],
    payable: false,
    type: "function"
}, {
    constant: true,
    inputs: [],
    name: "bank",
    outputs: [{
        name: "",
        type: "address"
    }],
    payable: false,
    type: "function"
}, {
    constant: false,
    inputs: [],
    name: "play",
    outputs: [],
    payable: true,
    type: "function"
}, {
    inputs: [],
    payable: false,
    type: "constructor"
}]

Rationale

This implementation uses a simplistic (almost)stochastic value from the following input data:

// Compute some *almost random* value for selecting winner from current transaction.
var random = uint(block.blockhash(block.number)) + block.timestamp + block.difficulty + block.number;

That computed value is far from beeing perfect but it's enough randomized for testing pourposes.

Blockchains are deterministic so it's difficult to provide a secure random source, but it's possible using some bridge between the Bitcoin blockchain & Ethereum smart contracts so instead using Ethereum block time, an automated lottery game can use higher block exchange rate from Bitcoin's blockchain increasing the entropy quality.

Verifying contract

If you need you can verify this smart contract in the public Ethereum blockchain explorer:

https://etherscan.io/address/0xa11e4ed59dc94e69612f3111942626ed513cb172

Testing

(assume you have created first etherbase account with some funding ether)

$ geth --syncmode "light"

$ geth account new
$ geth account new
$ geth account new

$ geth attach

> var myfunds = web3.eth.accounts[0]
> var a1 = web3.eth.accounts[1]
> var a2 = web3.eth.accounts[2]
> var a3 = web3.eth.accounts[3]

> personal.unlockAccount(myfunds)

> eth.sendTransaction({from: myfunds, to: a1, value: web3.toWei(.033, 'ether')})
> eth.sendTransaction({from: myfunds, to: a2, value: web3.toWei(.033, 'ether')})
> eth.sendTransaction({from: myfunds, to: a3, value: web3.toWei(.033, 'ether')})

> var etherlotto = eth.contract(
[{"constant":true,"inputs":[],"name":"pot","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"bank","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"play","outputs":[],"payable":true,"type":"function"},{"inputs":[],"payable":false,"type":"constructor"}]).at("0xa11e4ed59dc94e69612f3111942626ed513cb172")

> web3.eth.sendTransaction({from: a1, to: etherlotto.address, value: 10, data: etherlotto.play.getData()})