A Glitch Key-Gate for Logic Locking

Logic locking is a technique used for intellectual property protection. An effective attacking method based on satisfiability (SAT) algorithm, known as SAT attack, was proposed to decrypt an encrypted design successfully. To strengthen logic locking, this paper proposes a glitch-based logic locking method designed for sequential circuits. The proposed new schemes of key-gates can generate glitches, and use rising and falling transitions as key-inputs for the comprehensive logic locking. Experimental results show that the proposed glitch key-gate (GK) has high capability to be embedded in a set of IWLS2005 Benchmarks [22]. The cell area overhead in the designs encrypted with GKs are 10.68%, 12.22%, and 26.11% on average for encryptions with 8, 16, and 32 key-inputs, respectively, and the overhead can be reduced substantially when the GKs are combined with other logic locking methods.