The Sand Walker

Hackathon project at EthPrague 2023. Took inspiration from the Etherenauts project to learn Solidity, then adapted it to learn Cairo 1.

The Sand Walker is a community-driven StarkNet cybersecurity wargame built at EthPrague 2023, inspired by OpenZeppelin’s The Ethernaut. The project adapts the Capture The Flag (CTF) format for Cairo 1 smart contracts deployed on StarkNet.

Each level presents a Cairo smart contract with a vulnerability or puzzle. Players must analyse the contract, find the exploit, and call the right functions to “pwn” it. The live version is available at sandwalker.xyz.

Team

Built with Marina Cebotari, GianfrancoBazzani, and Roger over one weekend at EthPrague 2023.

Architecture

Smart Contracts (/contracts) — Cairo 1 contracts on StarkNet. The main TheSandWalker contract acts as a game registry: it tracks registered levels, player instances, and completion status. Players call create_instance() to deploy a personal challenge instance, then interact with it to find the solution.

Frontend (/client) — A Next.js 13 app with StarkNet wallet integration. Players connect their wallet, browse levels, and submit solutions directly from the browser.

Tech Stack

Layer Technology
Smart contracts Cairo 1, StarkNet
Frontend Next.js 13, React 18
Styling Tailwind CSS
Wallet starknet-react, get-starknet
Build tool Scarb (Cairo package manager)