Cross-chain relay architectures face critical security gaps: centralized trust dependencies, consensus vulnerabilities, and potential quantum threats. We propose the Quantum Cross-Chain (QCC) model—a post-quantum secure framework integrating quantum cryptography at the foundational layer. QCC establishes a global identity registry for heterogeneous chains and introduces a Two-Way Identity Authentication (TIA) protocol using GHZ entanglement, enabling information-theoretically secure mutual verification in a single execution. To fortify transaction integrity, we design a Quantum Ring Signature (QRS) scheme with novel key-loss security, ensuring that compromised keys cannot forge valid signatures. Unlike conventional systems that rely on smart contract autonomy, QCC delegates security to quantum one-way functions and distributed auditing, synchronizing consensus transmission with cryptographic validation. Formal verification proves composite security bounded by negl (n) + negl (q), while simulations demonstrate stable throughput (78. 5 TPS) and predictable latency (130 ms) under variable network conditions. QCC achieves post-quantum resilience, decentralized auditability, and linear scalability, providing a practical blueprint for next-generation cross-chain infrastructure.
Wang et al. (Thu,) studied this question.