Paper 2021/791

Open Sesame: A Novel Non-SAT-Attack against CAS-Lock

Akashdeep Saha, Urbi Chatterjee, Debdeep Mukhopadhyay, and Rajat Subhra Chakraborty


CAS-Lock (proposed in CHES2020), is an advanced logic locking technique that harnesses the concept of single-point function in providing SAT-attack resiliency. It is claimed to be powerful and efficient enough in mitigating state-of-the-art attacks against logic locking techniques. Despite the security robustness of CAS-Lock as claimed by the authors, we expose a serious vulnerability by exploiting the same and device a novel attack algorithm. The proposed attack can reveal the correct key by extracting the Distinguishing Input Patterns (DIPs) pertaining to a carefully chosen key simulation of the locked design. The correct key is obtained from the combination of elements from the set of extracted DIPs. Our attack is successful against various AND/OR cascaded-chain configurations of CAS-Lock and reports a 100% success rate in recovering the correct key.

Available format(s)
Publication info
Preprint. MINOR revision.
CAS-LockLogic LockingDistinguishing Input Pattern
Contact author(s)
akashdeepsaha95 @ gmail com
urbi ism @ gmail com
debdeep mukhopadhyay @ gmail com
rschakraborty @ gmail com
2021-06-14: received
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Creative Commons Attribution


      author = {Akashdeep Saha and Urbi Chatterjee and Debdeep Mukhopadhyay and Rajat Subhra Chakraborty},
      title = {Open Sesame: A Novel Non-SAT-Attack against CAS-Lock},
      howpublished = {Cryptology ePrint Archive, Paper 2021/791},
      year = {2021},
      note = {\url{}},
      url = {}
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