Security Problems of Latest FPGAs and Reverse Engineering Methods of Xilinx 7-series FPGAs

Field programmable gate arrays (FPGA) are commonly used in modern electronic applications, such as home appliances, automobiles, aerospace applications, and Internet of Things (IoT). However, security research is still insufficient compared to the rapidly developing design using FPGA. Attackers frequently attempt to hack into the vulnerable security of FPGA and introduce malicious codes, such as trojan. To defend against these attacks, it is necessary to determine the structure of FPGA accurately and study hackers' attacks. In this paper, we first explain the basic structure of FPGA, bitstream generation process, bitstream format, and structural differences between the Xilinx Vivado and ISE tools. We also reveal the vulnerabilities of the encryption method of IEEE 1735, which is widely used as a security method, and introduce security vulnerabilities to representative FPGA suppliers using IEEE 1735. Moreover, we analyze the security issues that can occur during the bitstream generation process and explain the recent research trend of reverse engineering against these security vulnerabilities.