Locking by Untuning: A Lock-Less Approach for Analog and Mixed-Signal IC Security

• Published in: IEEE transactions on very large scale integration (VLSI) systems Vol. 29; no. 12; pp. 2130 - 2142
• Main Authors: Elshamy, Mohamed, Sayed, Alhassan, Louerat, Marie-Minerve, Aboushady, Hassan, Stratigopoulos, Haralampos-G.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Analog circuits; Analog to digital conversion; Analog to digital converters; Calibration; Cloning; Computer crime; Computer Science; Configurations; Cryptography and Security; Engineering Sciences; Foundries; hardware security and trust; Integrated circuits; Intellectual property; intellectual property (IP)/integrated circuit (IC) piracy; Keys; Locking; Manufacturing; Micro and nanotechnologies; Microelectronics; mixed-signal ICs; Security; Security management; Transistors; Tuning
• ISSN: 1063-8210; 1557-9999
• DOI: 10.1109/TVLSI.2021.3117584

We propose an antipiracy security approach for programmable analog and mixed-signal (AMS) integrated circuits (ICs). The security approach relies on functionality locking by leveraging the inherent programmability and utilizing the configuration settings as secret keys or, equivalently, the programming bits as key bits. When invalid keys are applied, the circuit is untuned and, as a result, its functionality breaks, i.e., at least one of the performances violates its specification. As long as the calibration algorithm that produces the configuration settings can be kept secret, the proposed approach can serve as a countermeasure against all types of counterfeiting, i.e., cloning, overbuilding, remarking, and recycling. An important advantage of the proposed approach is that it is lock-less. It leaves the design intact, there is no change to the design flow, and there are no performance penalty and no area or power overheads due to the lock operation. We demonstrate it on a <inline-formula> <tex-math notation="LaTeX">\Sigma \Delta </tex-math></inline-formula> analog-to-digital converter (ADC) with 194-bit programmability and complex calibration algorithm used in the context of highly digitized, multistandard RF receivers.