Write Up/Ethernaut - 블록체인 워게임18 Ethernaut - 13단계 (Gatekeeper One) // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract GatekeeperOne { address public entrant; modifier gateOne() { require(msg.sender != tx.origin); _; } modifier gateTwo() { require(gasleft() % 8191 == 0); _; } modifier gateThree(bytes8 _gateKey) { require(uint32(uint64(_gateKey)) == uint16(uint64(_gateKey)), "GatekeeperOne: invalid gateThree part one"); require(uint32(uint64(_gateKe.. 2023. 11. 20. Ethernaut - 12단계 (Privacy) // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract Privacy { bool public locked = true; uint256 public ID = block.timestamp; uint8 private flattening = 10; uint8 private denomination = 255; uint16 private awkwardness = uint16(block.timestamp); bytes32[3] private data; constructor(bytes32[3] memory _data) { data = _data; } function unlock(bytes16 _key) public { require(_key == bytes.. 2023. 11. 18. Ethernaut - 11단계 (Elevator) // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; interface Building { function isLastFloor(uint) external returns (bool); } contract Elevator { bool public top; uint public floor; function goTo(uint _floor) public { Building building = Building(msg.sender); if (! building.isLastFloor(_floor)) { floor = _floor; top = building.isLastFloor(floor); } } } This elevator won't let you reach the .. 2023. 11. 17. Ethernaut - 10단계 (Re-entrancy) // SPDX-License-Identifier: MIT pragma solidity ^0.6.12; import 'openzeppelin-contracts-06/math/SafeMath.sol'; contract Reentrance { using SafeMath for uint256; mapping(address => uint) public balances; function donate(address _to) public payable { balances[_to] = balances[_to].add(msg.value); } function balanceOf(address _who) public view returns (uint balance) { return balances[_who]; } functi.. 2023. 11. 16. 이전 1 2 3 4 5 다음
