Mitigating Electro-Optical Frequency Mapping Attacks on Logic-Locked Integrated Circuits

The outsourcing of integrated circuit (IC) fabrication raises concerns of reverse-engineering, piracy, and overproduction of high-value intellectual property (IP). Logic locking was developed to address this by adding logic gates to a design to a chip’s functionality during fabrication. However, recent advances have revealed that logic locking is susceptible to physical probing attacks, such as electro-optical frequency mapping (EOFM). In this work, we propose Adjoining Gates , a novel logic locking enhancement that places auxiliary logic gates near gates that leak key information when probed to obscure them, thereby mitigating EOFM-style attacks. To implement Adjoining Gates, we developed an open-source security verification and design automation algorithm that detects EOFM key leakage during placement and inserts Adjoining Gates in a design. Our evaluation shows that our proposed approach identified and mitigated all EOFM-extractable key leakage across 16 benchmarks of varying sizes, locking techniques, and probe resolutions with a 4.15% average gate count overhead.