Polkadot_Championship_Chall.../Prequalification_Challenges/entry_solidity/easy.sol

33 lines
1.1 KiB
Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract PolkadotCTF {
address public winner;
event FlagCaptured(address indexed player);
// Encoded parts of the flag as byte arrays
bytes private part1 = hex"50437b497354686973";
bytes private part2 = hex"546865466c61674f72";
bytes private part3 = hex"644e6f747d";
// Function to decode the parts and get the full flag
function decodeFlag() public view returns (string memory) {
return string(abi.encodePacked(part1, part2, part3));
}
// Function to capture the flag
function captureFlag(string memory _solution) public {
string memory decodedFlag = decodeFlag();
require(keccak256(abi.encodePacked(_solution)) == keccak256(abi.encodePacked(decodedFlag)), "Incorrect solution");
winner = msg.sender;
emit FlagCaptured(msg.sender);
}
// Function to get the flag
function getFlag() public view returns (string memory) {
require(msg.sender == winner, "You are not the winner");
return decodeFlag();
}
}