Challenge #5: 📺 A State Channel Application Challenge

Tasks to be done

🧑‍🤝‍🧑 State channels really excel as a scaling solution in cases where a fixed set of participants want to exchange value-for-service at high frequency. The canonical example is in file sharing or media streaming: the server exchanges chunks of a file in exchange for micropayments.

🧙 In our case, the service provider is a Guru who provides off-the-cuff wisdom to each client Rube through a one-way chat box. Each character of text that is delivered is expected to be compensated with a payment of 0.001 ETH.

We will:

• 🛣️ Build a Streamer.sol contract that collects ETH from numerous client addresses using a payable fundChannel() function and keeps track of balances.
• 💵 Exchange paid services off-chain between the Streamer.sol contract owner (the Guru) and rube clients with funded channels. The Guru provides the service in exchange for signed vouchers which can later be redeemed on-chain.
• ⏱ Create a Challenge mechanism with a timeout, so that rubes are protected from a Guru who goes offline while funds are locked on-chain (either by accident, or as a theft attempt).
• ⁉ Consider some security / usability holes in the current design.

My Review

This challenge helps you dive into layer 2 solutions in blockchain ⛓️ State channels is one of the solutions but I also got to explore and learn more about rollups (ZK Rollup and Optimistic rollups). I also learned how to verify a message singature on chain using ecrecover function as well as I explored the openzeppelin's ECDSA library 🔍 It also made me explore Broadcast channels in js since, I spend hours understanding why my messages aren't being sent via the channel when I had the second tab open in incognito (messages only pass in the same window!) 🙂

Important links

• Speed Run Ethereum
• Deployed webapp
• Deployed contract
• Project source code