Truly Stripping Functionality for Logic Locking: A Fault-Based Perspective

Abhrajit Sengupta, Mohammed Nabeel, Nimisha Limaye, Mohammed Ashraf, Ozgur Sinanoglu

Research output: Contribution to journalArticlepeer-review


Logic locking is a holistic solution to counter manufacturing threats, such as intellectual property (IP) piracy and overbuilding at the hardware level. However, years of research has exposed various flaws in locking, including a Boolean satisfiability (SAT)-based attack. Consequently, several SAT-resilient locking techniques, such as SARLock, Anti-SAT, and SFLL have been proposed, although certain instances of them have also been broken by a class of attacks, called removal attack. In this article, we approach logic locking by leveraging well-known principles from very large-scale integration (VLSI) testing and elicit logic locking properties that dictate the resilience of a locking technique against different attacks. We present a revised version of SFLL, namely SFLL-rem, that not only retains all security properties of SFLL, delivering resilience to all the state-of-the-art attacks SFLL can thwart, but also to the latest removal attacks that broke some SFLL instances. Further, we develop a security-aware CAD framework integrated with industry tools that incurs only -1.5%, 0%, and 4.13% overhead for power, performance, and area, respectively. We demonstrate a silicon implementation of SFLL-rem on ARM Cortex-M0 microprocessor in 65 nm. Moreover, we provide a framework for an SoC designer to customize logic locking based on the SoC blocks and their threat models; this is illustrated by locking a multimillion-gate SoC provided by DARPA, and taking the SoC all the way to GDSII layout.

Original languageEnglish (US)
Article number8967131
Pages (from-to)4439-4452
Number of pages14
JournalIEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Issue number12
StatePublished - Dec 2020


  • ATPG
  • SFLL
  • intellectual property (IP) piracy
  • logic locking
  • removal

ASJC Scopus subject areas

  • Software
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering


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