Exploiting Principle of Moving Target Defense to Secure FPGA Systems

Field Programmable Gate Arrays (FPGAs) enter a rapid growth era due to their attractive flexibility and CMOS-compatible fabrication process. However, the increasing popularity and usage of FPGAs also drive more motivated attacks on FPGA systems. In this work, we extensively investigate new potential attacks originated from the untrusted computer-aided design (CAD) suite for FPGAs and further propose a series of countermeasures. For the scenario of using FPGAs to replace obsolete components in legacy systems, we propose a Runtime Pin Grounding (RPG) scheme to ground the unused pins and check the pin status at every clock cycle, and exploit the principle of moving target defense (MTD) to develop a hardware MTD (HMTD) method to thwart hardware Trojan attacks. For general FPGA applications, we extend HMTD to an FPGA-oriented MTD (FOMTD) method, which is composed of three defense lines. FPGA emulation results and hardware cost analyses show that the proposed countermeasures are capable of tackling the attacks from malicious CAD tools with acceptable overheads.