ETH93 - Daily lotteries on the blockchain
The ETH93 smart contract offers a simple, entirely transparent lottery game running off the Ethereum blockchain. Each day, a lottery is held, and a random number is generated to determine the winner. Proceeds from ticket sales are distributed as follows:
Tickets cost 0.01 Ether (no fiat currency is exchanged) and users are able to purchase an unlimited number of tickets in each daily lottery. The more people participate in each days lottery, the lower your chance of winning but the higher the jackpot.
Participate in today's lottery
Advantages of ETH93
Transparency: The smart contract behind this lottery is run on the Ethereum blockchain and thus everything can be made 100% transparent, unlike with a regular website where users have no idea what code is actually running behind closed doors. For those unfamiliar, Solidity 'smart contracts' are essentially small pieces of software that run on the Ethereum blockchain, and smart contract code can be verified on Etherscan.io so others can see exactly what the contract does. We see transparency in how this works as an absolute necessity, and a major advantage offered by blockchain technology.
Decentralization: Running on the Ethereum blockchain also allows for our lottery to be entirely decentralized, so no website or central server is necessary (this website only exists to give information on the ETH93 lottery - the real product is the smart contract that runs on the Ethereum blockchain. As such, if this website were to go down it would have no effect on the lottery running each day).
High payouts with a cut for charity: ETH93 is also unique in that it offers a very high payout compared to most lotteries (93% of all ticket sales) together with 5% of ticket sales going to a worthy cause. To our knowledge this is the only functional decentralized Ethereum app where a portion of revenue goes to an established charity.
About Heifer International
The organization receiving 5% of all ticket sales is Heifer International, which was founded in 1944 and aims to reduce hunger and poverty. Heifer has helped over 15.5 million families in more than 125 countries, and has net assets well in excess of $100m. As listed on their website here, Heifer's Ethereum donation address is 0xdd2ee38f9993c0bc1c1b5b9798bc4deff66cac4a, which is what we have hardcoded in our smart contract.
Why Heifer International? We believe this to be the most trustworthy and deserving organization that we are able to contribute to, with a proven history and clear goals. As Ethereum is still very new technology, few charities at this stage have an Ethereum donation address, and this limits us in who we can donate to for the time being (since only Ether is exchanged through our lottery, we can only donate Ether - not fiat currency), but in any case Heifer International is a worthy recipient.
As should be obvious, Heifer International is not affiliated with us in any way and hasn't contributed to or endorsed this service.
How the lottery works
It is our aim to keep this lottery as simple as possible - run once a day, a random number generation to pick a winner at the end of the lottery, and Ether dispersed automatically. This is all easily achievable with Solidity smart contracts. You can view our verified smart contract on Etherscan.io here.
To determine a winner of a lottery, a random number between 0 and the number of tickets purchased minus 1 is generated. For example, if 500 tickets were sold, a random number between 0 and 499 would be generated. If the random number generated was 233, the owner of the 234th ticket purchased would be the winner. At a ticket cost of 0.01 Ether, the winner of this lottery would receive (0.01 * 500 * 0.93) = 4.65 Ether and Heifer International would receive (0.01 * 500 * 0.05) = 0.25 Ether.
Random numbers are generated through Random.org, which has been around for nearly 20 years and has established itself as by far the most popular and reliable random number generation service online. Random.org generates entirely random numbers via atmospheric noise. As taken from their website:
RANDOM.ORG offers true random numbers to anyone on the Internet. The randomness comes from atmospheric noise, which for many purposes is better than the pseudo-random number algorithms typically used in computer programs. People use RANDOM.ORG for holding drawings, lotteries and sweepstakes, to drive online games, for scientific applications and for art and music. The service has existed since 1998 and was built by Dr Mads Haahr of the School of Computer Science and Statistics at Trinity College, Dublin in Ireland. Today, RANDOM.ORG is operated by Randomness and Integrity Services Ltd.
As of today, RANDOM.ORG has generated 1.56 trillion random bits for the Internet community.
To access the Random.org API through our smart contract, the Oraclize smart contract is used. Oraclize is a well known service among Solidity developers which allows smart contracts like ours to interact with eternal API's and fetch data from the outside world.
In order to raise funds for future development and advertise ETH93 more widely, we are offering an ETH93 token where tokenholders are able to grab part of the proceeds of lotteries (up to 1% of all tickets sold). ETH93 tokens will be available to purchase after we've run several lotteries and have a reasonable userbase. Read more about the crowdsale here.
Get in touch
Please email email@example.com. To keep up with our developments follow our Twitter feed at twitter.com/ethereum93.
In participating in any lotteries from the ETH93 smart contract, you confirm that you are at least 18 years of age and you represent, warrant and agree to ensure that your use of our services will comply with all applicable laws, statutes and regulations. ETH93.com accepts no responsibility or liability for any losses which may be incurred by any person or persons using the ETH93 smart contract.
Smart contract code
View the complete verified contract code on Etherscan here, which includes the Oraclize contract - below is just the E93 contract. If you are a developer, we strongly welcome any feedback, and encourage anyone doubting the legitimacy of this lottery to go through the code themselves.