Structural analysis attack on finite state machine obfuscated circuits
In this letter, a structural analysis attack is explored as the first kind of attack to disclose the secret key of the circuit encrypted by the latest obfuscation technique JANUS‐HD. By extracting the finite state machine (FSM) diagram from the circuit and converting structural traces into constrain...
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Veröffentlicht in: | Electronics letters 2023-03, Vol.59 (5), p.n/a |
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Sprache: | eng |
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Zusammenfassung: | In this letter, a structural analysis attack is explored as the first kind of attack to disclose the secret key of the circuit encrypted by the latest obfuscation technique JANUS‐HD. By extracting the finite state machine (FSM) diagram from the circuit and converting structural traces into constraints, the secret key can be deduced by the CP‐SAT solver within a few minutes or even seconds in most cases. Incorrect keys can be further pruned by sequential equivalence checking with several oracles in case more than one key is obtained. The entire attack procedure lasts no longer than a few hours even for an FSM with 4096 states.
In this letter, the attack of JANUS‐HD obfuscated circuits is first modelled as a constraint programming (CP) problem. The previously unsolvable problem is made solvable by converting the structural traces of the finite state machine (FSM) into concise constraints. The attack efficiency is significantly improved by using compressed matrices and optimizing the way the CP‐SAT solver is called, especially for large FSMs. |
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ISSN: | 0013-5194 1350-911X |
DOI: | 10.1049/ell2.12748 |