No abstract

The globalized supply chain in the semiconductor industry raises several security concerns such as IC overproduction, intellectual property piracy and design tampering. Logic locking has emerged as a Design-for-Trust countermeasure to address these issues. Original logic locking proposals provide a high degree of output corruption -i.e., errors on circuit outputsunless it is unlocked with the correct key. This is a prerequisite for making a manufactured circuit unusable without the designer's intervention. Since the introduction of SAT-based attacks -highly efficient attacks for retrieving the correct key from an oracle and the corresponding locked design -resulting design-based countermeasures have compromised output corruption for the benefit of better resilience against such attacks. Our proposed logic locking scheme, referred to as SKG-Lock, aims to thwart SAT-based attacks while maintaining significant output corruption. The proposed provable SAT-resilience scheme is based on the novel concept of decoy key-inputs. Compared with recent related works, SKG-Lock provides higher output corruption, while having high resistance to evaluated attacks.

The current trend to globalize the supply chain in the Integrated Circuits (ICs) industry has raised several security concerns including, among others, IC overproduction. Over the past years, logic locking has grown into a prominent countermeasure to tackle this threat in particular. Logic locking consists of “locking” an IC with an added primary input, the so-called key, which, unless fed with the correct secret value, renders the ICs unusable. One of the first criteria ensuring the quality of a logic locking technique was the output corruption, i.e., the corruption at the outputs of a locked circuit, for any wrong key value. However, since the introduction of SAT-based attacks, resulting countermeasures have compromised this criterion in favor of a better resilience against such attacks. In this work, we propose SKG-Lock+, a Provably Secure Logic Locking scheme that can thwart SAT-based attacks while maintaining significant output corruption. We perform a comprehensive security analysis of SKG-Lock+ and show its resilience against SAT-based attacks, as well as various other state-of-the-art attacks. Compared with related works, SKG-Lock+ provides higher output corruption and incurs acceptable overhead.