Design and Performance Evaluation of Binary Code Packing for Protecting Embedded Software against Reverse Engineering

Packing (or executable compression) is considered as one of the most effective anti-reverse engineering methods in the Microsoft Windows environment. Even though many reversing attacks are widely conducted in the Linux-based embedded system there is no widely used secure binary code packing tools for Linux. This paper presents two secure packing methods that use AES encryption and the UPX packer to protect the intellectual property (IP) of software from reverse engineering attacks on Linux-based embedded system. We call these methods: secure UPX and AES-encryption packing. Since the original UPX system is designed not for software protection but for code compression, we present two anti-debugging methods in the unpacking module of the secure UPX to detect or abort reverse engineering attacks. Furthermore, since embedded systems are highly resource constrained, minimizing unpacking overhead is important. Therefore, we analyze the performance of the two packing methods from the perspective of: (i) code size, (ii) execution time, and (iii) power consumption. Our analysis results show that the Secure UPX performs better than AES-encryption packing in terms of the code size, execution time, and power consumption.