Improving hardware Trojan detection using scan chain based ring oscillators

Abstract

In recent years, the security of integrated circuits (ICs) has received more attention as usage of ICs made by untrustworthy foundries has increased in safety-critical systems [1]. In this paper, we introduce a novel approach for fingerprinting the delay of functional paths in a sequential circuit that have millions of transistors, like processors. We present a method for inserting Ring Oscillators (ROs) into scan chain for measuring the delay of each functional path inside the chip.Using the proposed method, the payload part of Trojans will be detected according to their size and cell types. Our method can be used by power-based Trojan detection approaches for finding the trigger part of Trojans. We also introduce an algorithm for quantifying the vulnerability of the nets. We show that a designer can achieve a good trade-off between area overhead reduction and security enhancement while evaluating the vulnerability degree of each net.