Transition probabilistic approach for detection and diagnosis of Hardware Trojan in combinational circuits

Traditionally, Hardware is considered as root of trust. Software generally builds on top of the hardware. By emerging Hardware Trojan attacks, this trust seems to be violated. Hardware Trojan is any addition or modification to a circuit or a system with malicious intention. Trojan can cause change or control over functionality in circuit or it may leak sensitive information from inside the chip and hence reduce circuit reliability. In this paper, we analyze threats caused by hardware Trojan attacks and type of hardware Trojans. We have discussed state-of-art hardware Trojan protection schemes. The limitations and challenges related to those trojan detection schemes are described. We also propose simple but effective probabilistic method to detect and find the location of hardware trojan in combinational circuits. The experimental results for a series of ISCAS85 benchmark circuits show that better trojan detection rate or coverage can be achieved with proposed technique.