Capacity Smart Contracts

Ethereum smart contracts supporting Flexa capacity wallets

Audit

The contract code was audited by Trail of Bits over the course of two weeks in September 2019. Note that root commit of this repository contains the final version of the contract as referenced on page 26 of the audit report.

Requirements

• NodeJS

Running locally

In order to run the contracts locally,

• Compile the smart contracts
• Start the Truffle development console
• Deploy the smart contracts

$ cd /path/to/capacity-smart-contracts
$ npm install                   // Install the required NPM packages (truffle and openzeppelin-solidity for now)
$ truffle compile               // compiles the smart contracts
$ truffle develop               // starts the truffle development console, including a local blockchain
Truffle Develop started at http://127.0.0.1:9545/
...
truffle(develop)> deploy        // deploys the smart contracts
Starting migrations...
...
   Deploying 'Staking'
   -------------------
   > transaction hash:    0x713118674a2d2d33965896000d0608fc742d4e168200183661e45ae2440b3c8d
   > Blocks: 0            Seconds: 0
   > contract address:    0x62395D7FF20eBae660b0d212f47E823Ad4Cc1Db2
   > account:             0x93606DdFd78D741B6f9d6D572E8b9bfEcB32930B
   > balance:             99.88672006
   > gas used:            3964787
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.07929574 ETH

   > Saving artifacts
   -------------------------------------
   > Total cost:          0.10776974 ETH
...

Now that the contracts are deployed, you can interact with them within the Truffle development console:

truffle(develop)> const staking = await Staking.deployed()
truffle(develop)> await staking._withdrawalPublisher() // simply hitting a getter function.
'0x369CCCb3bF65a6D44C2CE65CAC45Bc02D4052Aa2'

For testing locally, we've deployed a vanilla ERC-20 (TFXC) token to mimic FXC. You'll need to grant the FlexaStakingWallet contract access to deposit your TFXC funds:

truffle(develop)> const token = await LocalFXCToken.deployed()
truffle(develop)> await token.approve(staking.address, 100)  // Approve 100 TFXC for deposit

Now you may test deposit, withdrawal, etc.

truffle(develop)> await staking.deposit(100)
truffle(develop)> await staking._nonceToPendingDeposit(1)
Result {
  '0': '<your account address here>',
  '1':
   BN {
     negative: 0,
     words: [ 100, <1 empty item> ],
     length: 1,
     red: null },
  depositor: '<your account address here>',
  amount:
   BN {
     negative: 0,
     words: [ 100, <1 empty item> ],
     length: 1,
     red: null } }
truffle(develop)> const account = (await web3.eth.getAccounts())[0]
truffle(develop)> await staking.withdraw(account, 100, 1, [])
{ Error: Returned error: VM Exception while processing transaction: revert Root hash unauthorized -- Reason given: Root hash unauthorized. ...
// Error because the authorization for this withdrawal doesn't exist

Automated Tests

Tests are divided between unit tests and integration tests, which can be run with:

cd /path/to/capacity-smart-contracts
truffle test

Deploying

Rinkeby

Setup:

1. Create a .env file of the same format as .example.env but with the correct mnemonic and infura Rinkeby Key

2. Uncomment the following in truffle-config.js:

    //    optimizer: {
    //      enabled: true,
    //      runs: 200
    //    },

Deployment

Clean start migration: truffle migrate --network rinkeby --reset --compile-all

OR

Incremental migration: truffle migrate --network rinkeby --compile-all

Test

Open up the truffle console pointed to rinkeby: truffle console --network rinkeby

truffle(rinkeby)> const staking = await Staking.deployed()
truffle(rinkeby)> const fxcAddress = await staking._tokenAddress()
truffle(rinkeby)> fxcAddress
> // this should be the deployed LocalFXCToken address 
truffle(rinkeby)> const token = await LocalFXCToken.deployed()
truffle(rinkeby)> const balance = await token.balanceOf('0x369CCCb3bF65a6D44C2CE65CAC45Bc02D4052Aa2')
truffle(rinkeby)> balance.toString()
> '1000000000000000000000000' // Initial supply of test FXC

License

MIT