关键词: 硬件木马, 转换概率, 环形振荡器（RO）, 木马检测

Abstract: In view of the problem that hardware Trojans tend to insert in low transition probability nodes in circuits, a method of constructing a Ring Oscillator（RO） structure at these nodes is proposed to detect hardware Trojans. The method first calculates the transition probability of the circuit node and selects the nodes’ transition probability below the threshold, then constructs the RO structure at the selected node, and detects the Trojan through the change of the RO delay. The experiment is based on the ISCAS’85 benchmarks and is implemented on the Spartan6 FPGA development board. The experimental results show that under the acceptable area and power consumption, small Trojan circuits with only one or two gates can be detected, which makes up for the shortcomings of side channel signal analysis to detect small Trojans.

Key words: hardware Trojan, transition probability, Ring Oscillator（RO）, Trojan detection