With Zeppelin, you can build distributed applications, protocols and organizations:
- using common contract security patterns (See [Onward with Ethereum Smart Contract Security](https://medium.com/bitcorps-blog/onward-with-ethereum-smart-contract-security-97a827e47702#.y3kvdetbz))
Zeppelin integrates with [Truffle](https://github.com/ConsenSys/truffle), an Ethereum development environment. Please install Truffle and initialize your project with `truffle init`.
> NOTE: The current distribution channel is npm, which is not ideal. [We're looking into providing a better tool for code distribution](https://github.com/OpenZeppelin/zeppelin-solidity/issues/13), and ideas are welcome.
We also support Truffle Beta npm integration. If you're using Truffle Beta, the contracts in `node_modules` will be enough, so feel free to delete the copies at your `contracts` folder. If you're using Truffle Beta, you can use Zeppelin contracts like so:
Zeppelin is meant to provide secure, tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problem you might experience.
Sets the address of the creator of the contract as the owner.
#### modifier onlyOwner( )
Prevents function from running if it is called by anyone other than the owner.
#### transfer(address newOwner) onlyOwner
Transfers ownership of the contract to the passed address.
---
### Stoppable
Base contract that provides an emergency stop mechanism.
Inherits from contract Ownable.
#### emergencyStop( ) external onlyOwner
Triggers the stop mechanism on the contract. After this function is called (by the owner of the contract), any function with modifier stopInEmergency will not run.
#### modifier stopInEmergency
Prevents function from running if stop mechanism is activated.
Adds sent amount to available balance that payee can pull from this contract, called by payer.
#### withdrawPayments( )
Sends designated balance to payee calling the contract. Throws error if designated balance is 0, if contract does not hold enough funds ot pay the payee, or if the send transaction is not successful.
___
### StandardToken
Based on code by FirstBlood: [FirstBloodToken.sol]
Inherits from contract SafeMath. Implementation of abstract contract ERC20 (see [https://github.com/ethereum/EIPs/issues/20])
Transfers tokens from an account that the sender is approved to transfer from. Amount must not be greater than the approved amount or the account's balance.
To create a bounty for your contract, inherit from the base `Bounty` contract and provide an implementation for `deployContract()` returning the new contract address.
```
import "./zeppelin/Bounty.sol";
import "./YourContract.sol";
contract YourBounty is Bounty {
function deployContract() internal returns(address) {
return new YourContract()
}
}
```
Next, implement invariant logic into your smart contract
At contracts/YourContract.sol
```
contract YourContract {
function checkInvariant() returns(bool) {
// Implement your logic to make sure that none of the state is broken.
}
}
```
Next, deploy your bounty contract along with your main contract to the network.
At `migrations/2_deploy_contracts.js`
```
module.exports = function(deployer) {
deployer.deploy(YourContract);
deployer.deploy(YourBounty);
};
```
Next, add a reward to the bounty contract
After deploying the contract, send reward funds into the bounty contract.
From `truffle console`
```
bounty = YourBounty.deployed();
address = 0xb9f68f96cde3b895cc9f6b14b856081b41cb96f1; // your account address
reward = 5; // reward to pay to a researcher who breaks your contract
web3.eth.sendTransaction({
from: address,
to: bounty.address,
value: web3.toWei(reward, "ether")
})
```
If researchers break the contract, they can claim their reward.
For each researcher who wants to hack the contract and claims the reward, refer to our [test](./test/Bounty.js) for the detail.
Finally, if you manage to protect your contract from security researchers, you can reclaim the bounty funds. To end the bounty, kill the contract so that all the rewards go back to the owner.
