Random for Solidity (eth-random)

Eth-Random is an Ethereum contract for generating pseudo-random numbers.

Our goal - Implementing the simplest and most efficient ways to generate a random number of arbitrary size over the Ethereum network.

The motivation for this project came from a need for a true and cheap way to create random assets. Despite a couple of posts and comments found on the internet, we couldn't find a single common resource. However, the beauty and strength of our approach comes from growth via developer usage! The more people using the same contract the more the internal seed value becomes unpredictable, generating stronger results.

Caveats

Firstly, the block timestamp is not terribly unpredictable and yet it's one of the strongest sources of entropy available in the blockchain along with contract's internal seed.

Ideally, the caller of Random function should have minimal interest in the result, nor let interested users choose at which block the contract will be called.

If security is a main focus, it may be best to look into purchasing an oracle solution such as oraclize

Usage

The Ethereum contract can be found at the following addresses:

Main net

random: 0x0230CfC895646d34538aE5b684d76Bf40a8B8B89 etherscan

Rinkeby (test)

random: 0x606b7f97bFEaCDf430059e6ef8918F2BaD1EF7FD etherscan

Ropsten (test)

random: 0x1637140C895e01d14be5a7A42Ec2c5BB22893713 etherscan

Using in truffle

Install with npm install eth-random

Initialize and use random

Once you've located the contract's address, you can initialize the API with the address.

import "eth-random/contracts/Random.sol";

contract Foo {
  Random api = Random(/* set address here */);

  function rollDice() returns (uint64) {
    return api.random(6);
  }
}

See a simple RPG example

Stats

Run 10,000 on a 1,000 range, using testrpc on locahost data spreadsheet. Distribution:

average: 503.3 std deviation: 287.3

Test

Have truffle framework and testrpc installed and running.

npm test

Contributing

Please see CONTRIBUTING.md

OhJia/eth-random