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To enable trust in the IC supply chain, logic locking as an IP protection technique received significant attention in recent years. Over the years, by utilizing Boolean satisfiability (SAT) solver and its derivations, many de-obfuscation attacks have undermined the security of logic locking. Nonetheless, all these attacks receive the inputs (locked circuits) in a very simplified format (Bench or remapped and translated Verilog) with many limitations. This raises the bar for the usage of the existing attacks for modeling and assessing new logic locking techniques, forcing the designers to undergo many troublesome translations and simplifications. This paper introduces the RANE Attack, an open-source CAD-based toolbox for evaluating the security of logic locking mechanisms that implement a unique interface to use formal verification tools without a need for any translation or simplification. The RANE attack not only performs better compared to the existing de-obfuscation attacks, but it can also receive the library-dependent logic-locked circuits with no limitation in written, elaborated, or synthesized standard HDL, such as Verilog. We evaluated the capability/performance of RANE on FOUR case studies, one is the first de-obfuscation attack model on FSM locking solutions (e.g., HARPOON) in which the key is not a static bit-vector but a sequence of input patterns.
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This content will become publicly available on March 1, 2026
Protecting Dynamically Obfuscated Scan Chain Architecture from DOSCrack with Trivium Pseudo-Random Number Generation
Design-for-test/debug (DfT/D) introduces scan chain testing to increase testability and fault coverage by inserting scan flip-flops. However, these scan chains are also known to be a liability for security primitives. In previous research, the dynamically obfuscated scan chain (DOSC) was introduced to protect logic-locking keys from scan-based attacks by obscuring test patterns and responses. In this paper, we present DOSCrack, an oracle-guided attack to de-obfuscate DOSC using symbolic execution and binary clustering, which significantly reduces the candidate seed space to a manageable quantity. Our symbolic execution engine employs scan mode simulation and satisfiability modulo theories (SMT) solvers to reduce the possible seed space, while obfuscation key clustering allows us to effectively rule out a group of seeds that share similarities. An integral component of our approach is the use of sequential equivalence checking (SEC), which aids in identifying distinct simulation patterns to differentiate between potential obfuscation keys. We experimentally applied our DOSCrack framework on four different sizes of DOSC benchmarks and compared their runtime and complexity. Finally, we propose a low-cost countermeasure to DOSCrack which incorporates a nonlinear feedback shift register (NLFSR) to increase the effort of symbolic execution modeling and serves as an effective defense against our DOSCrack framework. Our research effectively addresses a critical vulnerability in scan-chain obfuscation methodologies, offering insights into DfT/D and logic locking for both academic research and industrial applications. Our framework highlights the need to craft robust and adaptable defense mechanisms to counter evolving scan-based attacks.
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- Award ID(s):
- 2016624
- PAR ID:
- 10566291
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Cryptography
- Volume:
- 9
- Issue:
- 1
- ISSN:
- 2410-387X
- Page Range / eLocation ID:
- 6
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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