What you'll build: IPFS protocol implementation with gateway fallback and local daemon support.

What you'll learn: Content-addressed storage, CID parsing and verification, IPFS gateway API, DAG traversal for large files, IPNS (mutable content addresses).

End state: Task 20 completed. IpfsProtocol implementation can resolve CIDs via HTTP gateways or local IPFS daemon, handle multi-block DAG structures, and verify content hashes.