diff --git a/contracts/status/MessageDeliveryPayout.sol b/contracts/status/MessageDeliveryPayout.sol new file mode 100644 index 0000000..163df9d --- /dev/null +++ b/contracts/status/MessageDeliveryPayout.sol @@ -0,0 +1,79 @@ +pragma solidity ^0.4.17; + +import "../token/ERC20Token.sol"; + + +contract MessageDeliveryPayout { + + ERC20Token SNT; + mapping(bytes32 => bool) delivered; + + event Delivered(address indexed sender, bytes32 message); + + function MessageDeliveryPayout(ERC20Token _snt) public { + SNT = _snt; + } + + /** + * @notice confirms delivery of message and payouts to whoever delivered the message + * @notice `_sender` needs to approve against this contract, check _sender `SNT` token approval before trying to confirm; + * @param _sender the address of message sender + * @param _receiver the address of message destination + * @param _message the hash of the message + * @param _deliveryFee the amount willing to pay to deliver the message + * @param _senderSignature signature of contract address, message receiver, message hash, and delivery fee by `_sender` + * @param _receiverSignature signature of contract adress, message hash + */ + function confirmDelivery(address _sender, address _receiver, bytes32 _message, uint256 _deliveryFee, bytes _senderSignature, bytes _receiverSignature) public { + require(!delivered[_message]); + var (v,r,s) = signatureSplit(_senderSignature); + require(ecrecover(getSignedHash(keccak256(address(this), _receiver, _message, _deliveryFee)), v,r,s) == address(_sender)); + (v,r,s) = signatureSplit(_receiverSignature); + require(ecrecover(getSignedHash(keccak256(address(this), _message)), v,r,s) == address(_receiver)); + SNT.transferFrom(_sender, msg.sender, _deliveryFee); + delivered[_message] = true; + Delivered(_sender, _message); + } + + + /** + * @notice Hash a hash with `"\x19Ethereum Signed Message:\n32"` + * @param _hash Sign to hash. + * @return signHash Hash to be signed. + */ + function getSignedHash( + bytes32 _hash + ) + pure + public + returns(bytes32 signHash) + { + signHash = keccak256("\x19Ethereum Signed Message:\n32", _hash); + } + + /** + * @dev divides bytes signature into `uint8 v, bytes32 r, bytes32 s` + */ + function signatureSplit(bytes signature) + pure + private + returns (uint8 v, bytes32 r, bytes32 s) + { + // The signature format is a compact form of: + // {bytes32 r}{bytes32 s}{uint8 v} + // Compact means, uint8 is not padded to 32 bytes. + assembly { + r := mload(add(signature, 32)) + s := mload(add(signature, 64)) + // Here we are loading the last 32 bytes, including 31 bytes + // of 's'. There is no 'mload8' to do this. + // + // 'byte' is not working due to the Solidity parser, so lets + // use the second best option, 'and' + v := and(mload(add(signature, 65)), 0xff) + } + + require(v == 27 || v == 28); + } + +} \ No newline at end of file