Concurrent Structure-Independent Fault Detection Schemes for the Advanced Encryption Standard

The Advanced Encryption Standard (AES) has been lately accepted as the symmetric cryptography standard for confidential data transmission. However, the natural and malicious injected faults reduce its reliability and may cause confidential information leakage. In this paper, we study concurrent fault detection schemes for reaching a reliable AES architecture. Specifically, we propose low-cost structure-independent fault detection schemes for the AES encryption and decryption. We have obtained new formulations for the fault detection of SubBytes and inverse SubBytes using the relation between the input and the output of the S-box and the inverse S-box. The proposed schemes are independent of the way the S-box and the inverse S-box are constructed. Therefore, they can be used for both the S-boxes and the inverse S-boxes using lookup tables and those utilizing logic gates based on composite fields. Our simulation results show the error coverage of greater than 99 percent for the proposed schemes. Moreover, the proposed and the previously reported fault detection schemes have been implemented on the most recent Xilinx Virtex FPGAs. Their area and delay overheads have been compared and it is shown that the proposed schemes outperform the previously reported ones.