Re{solve} Hackathon Workshop: Native Bitcoin support for Starknet dApps

Summary of "Re{solve} Hackathon Workshop: Native Bitcoin support for Starknet dApps"

Key Technological Concepts and Features:

• Garden Finance Overview
  • Garden Finance is a decentralized, trustless, and fast Bitcoin bridge enabling cross-chain swaps primarily between Bitcoin and Starknet.
  • It supports atomic swaps using HTLCs (Hash Time Locked Contracts), enabling fully trustless cross-chain transactions without custody risks.
  • Garden claims to be one of the fastest Bitcoin bridges with swap completion times as low as 30 seconds and nearing $2 billion in total volume.
• HTLCs Explained
  • HTLCs are smart contracts that lock funds using two conditions:
    • A secret (hashlock) that must be revealed to claim funds.
    • A time lock allowing refund to the sender if the secret is not revealed within a specified time.
  • This mechanism ensures atomicity: either the swap happens on both chains or neither does, preventing loss of funds.
  • The swap process involves two parties (e.g., Alice and Bob) locking funds on their respective chains using the same secret hash, enabling secure cross-chain atomic swaps.
• Cross-chain Atomic Swaps
  • Alice locks BTC on Bitcoin chain with a secret hash and time lock.
  • Bob locks equivalent wrapped BTC (WBTC) on Starknet using the same secret hash.
  • Alice redeems Bob’s locked funds by revealing the secret, which Bob then uses to redeem Alice’s BTC on Bitcoin chain.
  • This process is fully trustless and decentralized.
• Garden API and Workflow
  • Garden provides an API for developers to integrate Bitcoin-Starknet bridging into their dApps easily.
  • Basic workflow with the API involves:
    1. Querying supported assets and pairs (e.g., BTC to WBTC).
    2. Getting a quote for the swap (amount and fiat value).
    3. Creating an order to register the swap intent.
    4. Initiating the order on the source chain.
    5. Automatic redemption handled by Garden’s backend.
  • The API supports gasless redemption, meaning users do not pay gas fees directly for claiming funds.
  • The secret hash is typically generated using the standard SHA-256 algorithm.
• Technical Details and Demo
  • The workshop included a live demo using a TypeScript script that interacts with Garden’s API to perform a BTC to Starknet WBTC bridge.
  • The demo transaction completed in approximately 21 seconds with negligible gas costs.
  • The script is well-commented and available in a public repository for hackathon participants to use and build upon.
  • Users need wallets on both chains (Bitcoin and Starknet) to participate in swaps.
  • Approval of tokens is required on Starknet before locking funds in the HTLC contract.
• Additional Resources and Support
  • Documentation for Garden Finance, including API references and HTLC concepts, is comprehensive and publicly available.
  • Testnet environments and faucets are provided for safe experimentation.
  • The workshop materials, recording, and all relevant links will be shared on the hackathon Telegram channel and the official hackathon webpage within 12 hours.
• Supported Chains and Assets
  • While the workshop focused on Bitcoin and Starknet, Garden supports multiple chains and assets for bridging.
  • Users can check supported assets and chains on Garden’s mainnet and testnet UIs.

Main Speakers / Sources:

• Raan from Garden Finance — primary presenter explaining Garden’s technology, HTLCs, atomic swaps, API usage, and live demo.
• Dragon — host/moderator facilitating the workshop and Q&A.
• Additional participants included hackathon attendees asking questions and engaging during the session.

Summary of Reviews, Guides, or Tutorials:

• The workshop served as a technical tutorial on using Garden Finance’s decentralized Bitcoin bridge for Starknet dApps.
• It included a conceptual explanation of HTLCs and atomic swaps, a step-by-step guide to the Garden API workflow, and a live coding demo with a TypeScript script.
• Documentation and code repositories were promised and shared for further learning and hackathon development.
• The session encouraged participant questions and provided clarifications on cryptographic and operational details of cross-chain swaps.