On the mitigation of Hardware Trojan attacks in embedded processors by exploiting a Hardware-based obfuscator

Due to the complexity of digital circuits manufacturing, nowadays most semi-conductor companies outsource part of the fabrication process, reducing both the production costs and the time-to-market. However, as untrusted parties are involved in the production-chain, new security risks arise, and the threat of Hardware Trojans is a serious concern for the producers of embedded devices. In this paper, we propose an on-chip software obfuscator aiming to reduce the activation probability of malicious components through software. Using a completely transparent hardware based solution, with a limited hardware and time overhead, the sequence of instructions is modified, eventually defusing Trojan activation sequences, yet guaranteeing the original functionalities. The methodology was implemented in a modified version of the OR1200 processor core, using a set of programs from the MiBench test suit, to demonstrate the method suitability.