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The advancing of reverse engineering techniques has complicated the efforts in intellectual property protection. Proactive methods have been developed recently, among which layout-level integrated circuit camouflaging is the leading example. However, existing camouflaging methods are rarely supported by provably secure criteria, which further leads to an over-estimation of the security level when countering latest de-camouflaging attacks, e.g., the SAT-based attack. In this paper, a quantitative security criterion is proposed for de-camouflaging complexity measurements and formally analyzed through the demonstration of the equivalence between the existing de-camouflaging strategy and the active learning scheme. Supported by the new security criterion, two camouflaging techniques are proposed, including the low-overhead camouflaging cell generation strategy and the AND-tree camouflaging strategy, to help achieve exponentially increasing security levels at the cost of linearly increasing performance overhead on the circuit under protection. A provably secure camouflaging framework is then developed combining these two techniques. The experimental results using the security criterion show that camouflaged circuits with the proposed framework are of high resilience against different attack schemes with only negligible performance overhead. [ABSTRACT FROM AUTHOR]

The SAT-based attacks are extremely successful in deobfuscating the traditional combinational logic locking and IC camouflaging schemes. While several SAT-resilient protection schemes that increase the minimum query count of the attack have been proposed recently, none of them satisfy the output corruptibility (error) criteria. Therefore, most of them were combined with high corruptibility schemes to achieve both corruptibility and high query count. These “compound” schemes are successful since existing SAT attacks are agnostic to the corruptibility of the protection scheme. In this paper, we propose an approximate SAT-based attack framework which focuses on the iterative convergence of an attack toward a better solution. This helps our attack reduce a compound scheme to a standalone SAT-resilient scheme. In addition, we relate the problem of minimum query count to a well-known graph problem, and we propose a novel technique to increase the corruptibility of SAT-resilient protection schemes in a controllable manner. This creates protection schemes that have both high query count and corruptibility. Furthermore, due to the approximation resiliency property of these schemes, approximate attacks provide no advantage over exact attacks when attacking them. [ABSTRACT FROM AUTHOR]