Secure FPGA Design by Filling Unused Spaces

Nowadays there are different kinds of attacks on Field Programmable Gate Array (FPGA). As FPGAs are used in many different applications, its security becomes an important concern, especially in Internet of Things (IoT) applications. Hardware Trojan Horse (HTH) insertion is one of the major security threats that can be implemented in unused space of the FPGA. This unused space is unavoidable to meet the place and route requirements. In this paper, we introduce an efficient method to fill this space and thus to leave no free space for inserting HTHs. Using a shift register in combination with gate-chain is the best way of filling unused space, which incurs a no increase in power consumption of the main design. Experimental results of implementing a set of IWLS benchmarks on Xilinx Virtex devices show that the proposed prevention and detection scheme imposes a no power overhead with no degradation to performance and critical path delay of the main design