迴路鎖是硬體安全領域中最先進的邏輯加密技術。與其他邏輯加密技術不同，它通過一種邏輯優化技術在電路中創建迴路，以混淆攻擊者。透過在電路中使用兩種類型的迴路序對，迴路鎖能夠同時使SAT Attack，Removal Attack和CycSAT無效。在本文中，我們分析了迴路鎖的加密機制，並提出了一種基於加密結構分析的攻擊方法。實驗結果展示了該攻擊方法的有效性和效率。進一步地，基於此攻擊方式，我們設計了新的加密結構用以強化迴路鎖的加密安全性。

LOOPLock is the state-of-the-art logic locking method in hardware security. Different from other logic locking methods, it creates cycles in the circuit by a logic optimization technique for obfuscating attackers. LOOPLock is able to invalidate SAT Attack, Removal Attack, and CycSAT simultaneously by introducing two types of cycle pairs in a circuit. In this work, we analyze LOOPLock's locking mechanism and propose an attacking approach based on locking structure analysis. Experimental results show the efficiency and effectiveness of the proposed attacking approach. With this attacking approach, designers could further strengthen the protection of LOOPLock.

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