去中心化金融（Decentralized Finance, DeFi）徹底改變了傳統金融體系，使無需授權的借貸操作成為可能。然而，現有的 DeFi 協議僅支援加密資產作為抵押品，限制了持有實體資產（Real-World Assets, RWAs）用戶的參與機會。為此，本文提出一個基於區塊鏈的點對點（P2P）借貸框架，將現實世界抵押品納入鏈上借貸流程，同時兼顧隱私保護與監管可追溯性。該系統採用基於身份的多重代理簽章（Identity-Based Multiproxy Signatures, IBMPS）實現安全的簽章授權，並結合零知識證明（Zero-Knowledge Proofs, ZKPs）在不洩漏敏感資訊的情況下進行貸款驗證。智能合約自動化處理放款與清算流程，確保透明且無需信任的執行機制。此外，簽章過程中內嵌的追蹤機制，允許在接獲合法監管請求時識別借款人身份。實驗評估顯示，與 Aave 與 Compound 等主流協議相比，本框架可顯著降低 Gas 成本、維持穩定的驗證延遲，並展現出更佳的擴展性。此一設計有效連接鏈下實體資產與鏈上流動性，提升金融普惠性，同時兼顧用戶隱私與法規合規性。;The rise of Decentralized Finance (DeFi) has revolutionized traditional financial systems by enabling permissionless lending and borrowing. However, existing DeFi protocols remain confined to crypto-asset collateral, limiting accessibility for users holding real-world assets (RWAs). This paper proposes a blockchain-based peer-to-peer (P2P) lending framework that integrates real-world collateral into on-chain lending operations while preserving privacy and supporting regulatory traceability. The proposed system employs Identity-Based Proxy Signatures (IBPS) to delegate signing authority securely and Zero-Knowledge Proofs (ZKPs) to conceal sensitive financial information during loan verification. Smart contracts automate loan disbursement and liquidation, ensuring transparent and trustless execution. A traceability mechanism embedded in the delegation process allows authorized entities to retrieve borrower identities under regulatory requests. Experimental evaluations demonstrate that the framework achieves low gas consumption, constant verification latency, and superior scalability compared to conventional protocols such as Aave and Compound. By bridging off-chain collateral with on-chain liquidity, the proposed scheme enhances financial inclusivity while preserving user confidentiality and compliance capabilities.
