Cryptographic Hash-Time-Locked Contracts (HTLC) with Passkey Abstraction for Cross-Chain Enterprise Settlement

Cross-chain atomic settlement between enterprise permissioned ledgers (e.g., Hyperledger Besu) and public Ethereum EVM networks is conventionally bottlenecked by third-party bridge custodian vulnerabilities, high gas execution overhead, and steep key management friction for enterprise consumers. To systematically resolve these critical hurdles, this study presents a novel cross-chain settlement framework integrating Cryptographic Hash-Time-Locked Contracts (HTLC) with ERC-4337 Account Abstraction and hardware-backed WebAuthn Passkey (secp256r1) signature authorization via the native EVM P256VERIFY precompiled contract (address 0x0100). The proposed protocol enforces trustless atomic state transitions across heterogeneous blockchain execution environments by combining cryptographic SHA-256 secret preimage locking H(s) with deterministic expiration timelocks τ. By incorporating the hardware-accelerated P256VERIFY precompile, signature verification gas consumption is reduced by 99.01% (from 348,120 gas to a constant 3,450 gas), enabling gasless, seedless cross-chain transaction authorization directly from smartphone WebAuthn Authenticators. Mathematical formal security proofs confirm atomicity, deadlock-freedom, and double-spend immunity across a 4-validator QBFT Besu network and public Ethereum testnet. Comprehensive empirical benchmarks demonstrate cross-chain settlement finality in under 1.25 seconds with zero counterparty default risk across 12 rigorous testing scenarios.