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

Abstract

We propose an anti-piracy 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 is no performance penalty and no area or power overheads due to the lock operation. We demonstrate it on a Σ∆ Analogto-Digital Converter (ADC) with 194-bit programmability and complex calibration algorithm used in the context of highlydigitized, multi-standard RF receivers.

Leaking Wireless ICs via Hardware Trojan-Infected Synchronization

“…If the attack is staged by the foundry, pre-silicon prevention methods include: (a) filling in all unused spaces on the layout, which are most likely insertion areas for the HT, with functional filler cells and checking if those have changed [53]; and (b) design obfuscation, for example using locking [54], [55], [56], [57], [58], [59], [60], camouflaging [61], [62], [63], or split manufacturing [64], [65], aiming at obscuring the circuit functionality so as to make it difficult for the attacker to insert the HT.…”

Run-Time Hardware Trojan Detection in Analog and Mixed-Signal ICs

“…For example, SSCF is a generic countermeasure that has shown to be very effective for AMS ICs since several parametric measurements can be defined on AMS ICs on which a HT inevitably leaves traces [45]. Design obfuscation techniques have also been recently proposed for AMS ICs, including locking [80]- [84] and camouflaging [85], [86]. IFT is adapted for AMS ICs in [87].…”