BMCP

Problem Statement

BMCP (Bitcoin Multichain Protocol) bridges Bitcoin and EVM chains with true cross-chain programmability. Users can trigger EVM transactions (DeFi swaps, token transfers, contract calls) by signing a Bitcoin transaction using native Schnorr signatures (Taproot/BIP340). The Cross-chain Relayer Engine (CRE) scans Bitcoin blocks and, on detection of valid, Schnorr-authenticated BMCP messages embedded in OP_RETURN, executes secure calls both offchain (risk management, validation) and onchain (contract invocation) across Polygon, Ethereum, and more—seamlessly leveraging Chainlink CCIP. BMCP ensures all flows remain trust-minimized, cryptographically anchored to Bitcoin finality, and composable across ecosystems.

Solution

Bitcoin Layer: Leverages Bitcoin Core v30.0’s OP_RETURN (100KB) and native Schnorr signatures (Taproot, BIP340) for message authentication. Any wallet (including hardware/Taproot-native) can create cross-chain instructions via simple Bitcoin sends.Protocol Encoding: BMCP messages employ a binary, chain-agnostic format with a 4-byte protocol ID (0x424d4350 = "BMCP"). Versioned, compact, and includes chain selector, target contract, ABI-encoded calldata, and replay protection fields.Relayer (CRE): Monitors Bitcoin mempool & blocks, extracts and validates Schnorr-authenticated BMCP messages. Bridges to Chainlink CCIP, mapping each Bitcoin TX to Any2EVM messages. Executes offchain policy checks, then triggers onchain function calls atomically.Smart Contracts: Modular Solidity receivers deployed to Polygon, Ethereum, and Base process and verify BMCP payloads. Supports generic function execution, Uniswap V3 swaps, ERC20/721 transfers, and custom DeFi integrations.Dashboard & SDK: TypeScript/React dashboard for encoding and sending BMCP messages, monitoring state, and simulating transactions. SDK provides complete encoding, signing (including Schnorr/Taproot), and decoding utilities.Advanced Features: Hybrid: CRE handles both purely offchain (policy, risk) and on-chain (EVM execution) triggers. Extensible: Ready for Lightning integration and any EVM chain supporting CCIP. Security: Full cryptographic traceability from Bitcoin to EVM, leveraging finality, risk management, and contract-level validation.