Embedded System Confidentiality Protection by Cryptographic Engine Implemented with Composite Field Arithmetic

Embedded systems are subjecting to various kinds of security threats. Some malicious attacks exploit valid code gadgets to launch destructive actions or to reveal critical details. Some previous memory encryption strategies aiming at this issue suffer from unacceptable performance overhead and resource consumption. This paper proposes a hardware based confidentiality protection method to secure the code and data stored and transferred in embedded systems. This method takes advantage of the I/D-cache structure to reduce the frequency of the cryptographic encryption and decryption processing. We implement the AES engine with composite field arithmetic to reduce the cost of hardware implementation. The proposed architecture is implemented on EP2C70 FPGA chip with OpenRisc 1200 based SoC. The experiment results show that the AES engine is required to work only in the case of I/D-cache miss and the hardware implementation overhead can save 53.24% and 13.39% for the AES engine and SoC respectively.