Research On Hardware Trojan Detection Method Based On Low Transition Probability Node Path Delay

With the rapid development of microelectronics and computer technology,integrated circuits(ICs)have been widely used in aviation,finance,medical and other industries,and have become an integral part of daily life.However,due to economic reasons,the separation of IC design and manufacturing has become a trend,which has led to chip security being threatened in some untrusted links.This separation manufacturing provides attackers with the opportunity to insert redundant circuits with malicious functions into the circuit,namely the hardware Trojan(HT).Under certain trigger conditions,HT will cause inestimable harm to the chip,such as modifying the circuit function,leak user information.Therefore,in order to ensure the safety and reliability of integrated circuits,research on hardware Trojan detection and prevention methods has become particularly important.Because of its high concealment,hardware Trojans have relatively rare triggering conditions,so they are more inclined to insert nodes with low transition probability in the circuit.This dissertation proposes a method to construct a ring oscillator(RO)structure at these low probability nodes to detect hardware Trojans.This method first calculates the transition probability of the circuit nodes and selects the nodes below the threshold of the transition probability,and then constructs the RO structure at the selected nodes,and detects the Trojan horse by changing the delay of the RO path.The experiment is based on the ISCAS'85 reference circuit and implemented on a Spartan6 FPGA development board.Experimental results show that this method can effectively detect the presence of HT in the circuit at a lower area and power consumption compared with the existing RON structure.The effectiveness of current Trojan detection methods based on side channel signals is limited by several factors,such as voltage,temperature,and process fluctuations.The second Trojan detection method studied in this paper is to construct a latch structure based on a feedback loop for Trojan detection.By selecting two paths with similar physical positions in the circuit as the feedback path,the influence of process fluctuations on the structure of the proposed method is reduced.Based on the difference in delay between the two paths,it is determined whether the latch output logic value changes to detect the presence of HT in the circuit.At the same time,in order to reduce the hardware overhead,a path with a low transition probability node in the circuit is constructed to build a latch structure.Experiments show that this method can effectively detect a Trojan circuit with only one logic gate,and can obtain the position information of the hardware Trojan in the chip circuit according to the experimental results,which is a supplement to the existing hardware Trojan detection method to detect small Trojans.