Logic locking is used to protect integrated circuits (ICs) from piracy and counterfeiting. An encrypted IC implements the correct function only when the right key is input. Many existing logic-locking methods are subject to the powerful satisfiability (SAT)-based attack. Recently, an Anti-SAT scheme has been developed. By adopting two complementary logic blocks that consist of AND/NAND trees, it makes the number of iterations needed by the SAT attack exponential to the number of input bits. Nevertheless, the Anti-SAT scheme is vulnerable to the later AppSAT and removal attacks. This article proposes a generalized (G-)Anti-SAT scheme. Different from the Anti-SAT scheme, a variety of complementary or non-complementary functions can be adopted for the two blocks in our G-Anti-SAT scheme. The Anti-SAT scheme is just a special case of our proposed design. Our design can achieve higher output corruptibility, which is also tunable, so that better resistance to the AppSAT and removal attacks is achieved. Meanwhile, unlike existing AppSAT-resilient designs, our design does not sacrifice the resistance to the SAT attack.

中文翻译：

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广义SAT抗攻击逻辑锁定


逻辑锁定用于保护集成电路 (IC) 免遭盗版和假冒。只有当输入正确的密钥时，加密的IC才能实现正确的功能。许多现有的逻辑锁定方法都受到基于可满足性（SAT）的强大攻击。最近，已经开发了Anti-SAT方案。通过采用两个由 AND/NAND 树组成的互补逻辑块，使得 SAT 攻击所需的迭代次数与输入位数成指数关系。然而，Anti-SAT 方案很容易受到后来的 AppSAT 和删除攻击。本文提出了一种广义的(G-)Anti-SAT方案。与Anti-SAT方案不同，我们的G-Anti-SAT方案中的两个块可以采用多种互补或非互补功能。 Anti-SAT 方案只是我们提出的设计的一个特例。我们的设计可以实现更高的输出损坏率，而且输出损坏率也是可调的，从而可以更好地抵抗 AppSAT 和删除攻击。同时，与现有的 AppSAT 弹性设计不同，我们的设计不会牺牲对 SAT 攻击的抵抗力。