Biblio

The separation of manufacturing and design processes in the integrated circuit industry to tackle the ever increasing circuit complexity and time to market issues has brought with it some major security challenges. Chief among them is IP piracy by untrusted parties. Hardware obfuscation which locks the functionality and modifies the structure of an IP core to protect it from malicious modifications or piracy has been proposed as a solution. In this paper, we develop an efficient hardware obfuscation method, called Mystic (Mystifying IP Cores), to protect IP cores from reverse engineering, IP overproduction, and IP piracy. The key idea behind Mystic is to add additional state transitions to the original/functional FSM (Finite State Machine) that are taken only when incorrect keys are applied to the circuit. Using the proposed Mystic obfuscation approach, the underlying functionality of the IP core is locked and normal FSM transitions are only available to authorized chip users. The synthesis results of ITC99 circuit benchmarks for ASIC 45nm technology reveal that the Mystic protection method imposes on average 5.14% area overhead, 5.21% delay overhead, and 8.06% power consumption overheads while it exponentially lowers the probability that an unauthorized user will gain access to or derive the chip functionality.

The rapid growth and globalization of the integrated circuit (IC) industry put the threat of hardware Trojans (HTs) front and center among all security concerns in the IC supply chain. Current Trojan detection approaches always assume HTs are composed of digital circuits. However, recent demonstrations of analog attacks, such as A2 and Rowhammer, invalidate the digital assumption in previous HT detection or testing methods. At the system level, attackers can utilize the analog properties of the underlying circuits such as charge-sharing and capacitive coupling effects to create information leakage paths. These new capacitor-based vulnerabilities are rarely covered in digital testings. To address these stealthy yet harmful threats, we identify a large class of such capacitor-enabled attacks and define them as charge-domain Trojans. We are able to abstract the detailed charge-domain models for these Trojans and expose the circuit-level properties that critically contribute to their information leakage paths. Aided by the abstract models, an information flow tracking (IFT) based solution is developed to detect charge-domain leakage paths and then identify the charge-domain Trojans/vulnerabilities. Our proposed method is validated on an experimental RISC microcontroller design injected with different variants of charge-domain Trojans. We demonstrate that successful detection can be accomplished with an automatic tool which realizes the IFT-based solution.

Hardware Trojans have become in the last decade a major threat in the Integrated Circuit industry. Many techniques have been proposed in the literature aiming at detecting such malicious modifications in fabricated ICs. For the most critical circuits, prevention methods are also of interest. The goal of such methods is to prevent the insertion of a Hardware Trojan thanks to ad-hoc design rules. In this paper, we present a novel prevention technique based on approximation. An approximate logic circuit is a circuit that performs a possibly different but closely related logic function, so that it can be used for error detection or error masking where it overlaps with the original circuit. We will show how this technique can successfully detect the presence of Hardware Trojans, with a solution that has a smaller impact than triplication.