Cyfrin/ctf

A minimal repo to create EVM/solidity capture the flags

CTF

A minimal repo to help create capture the flag (CTF) challenges.

Getting Started

Requirements

• Git
  • You'll know you've done it right if you can run git --version
• Foundry / Foundryup
  • This will install forge, cast, and anvil
  • You can test you've installed them right by running forge --version and get an output like: forge 0.2.0 (f016135 2022-07-04T00:15:02.930499Z)
  • To get the latest of each, just run foundryup

Quickstart

1. Install the package into your project.

forge install cyfrin/ctf --no-commit

2. Create a registration CTF contract

This will be the NFT contract, and the place you'll add challenge contracts to.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {CTFRegistry} from "lib/ctf/src/protocol/CTFRegistry.sol";

contract SimpleCTFRegistry is CTFRegistry {
    constructor() CTFRegistry("Our CTF", "CTF") {}
}

3. Create a challenge contract

You'll need to add the following functions:

• solveChallenge() - This is the optional function that will be called when a user solves the challenge. The more important part, is that you need something to call _updateAndRewardSolver() which will update the user's NFT with the challenge they solved.
• attribute() - This is the attribute that will be shown on the NFT.
• description() - This is the description that will be shown on the NFT.
• specialImage() - This is the image that will be shown on the NFT. There is a base NFT that will be used if this is left blank.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {Challenge} from "lib/ctf/src/protocol/Challenge.sol";

contract SimpleCTFChallenge is Challenge {
    string constant BLANK_TWITTER_HANDLE = "";

    constructor(address registry) Challenge(registry) {}

    function solveChallenge() external {
        _updateAndRewardSolver(BLANK_TWITTER_HANDLE);
    }

    function attribute() external pure override returns (string memory) {
        return "Getting learned!";
    }

    function description() external pure override returns (string memory) {
        return "This is a simple CTF challenge.";
    }

    function specialImage() external pure returns (string memory) {
        return BLANK_TWITTER_HANDLE;
    }
}

4. Deploy, and add the contract to the registry

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

import {Script} from "forge-std/Script.sol";
import {SimpleCTFChallenge} from "../test/mocks/SimpleCTFChallenge.sol";
import {SimpleCTFRegistry} from "../test/mocks/SimpleCTFRegistry.sol";

contract MockDeploy is Script {
    function run() external {
        SimpleCTFRegistry registry = new SimpleCTFRegistry();
        SimpleCTFChallenge challenge = new SimpleCTFChallenge(address(registry));
        registry.addChallenge(address(challenge));
    }
}