A novel countermeasure against fault injection attacks for AES-based cryptosystems

Substitution function in AES-Based cryptosystems is highly vulnerable to different security attacks specially fault injection attacks. This paper proposes an architectural level method to immune AES-based cryptosystem against fault injection attacks. The proposed method utilizes extra substitution tables to detect maliciously injected fault. Values of the proposed substitution tables are stored in modulo 32, 15, 31, 16 which are derived based on Chinese Reminder Theorem. In this way, an 8-bit value of each cell of traditional substitution table is distributed among at least two cells in the proposed substitution function. The proposed substitution architecture may be adapted with 2, 4, 6 SBox tables. As a case study, we have analyzed fault detection capability of the proposed substitution architecture when the traditional substitution table is replaced with four modulo tables i.e., 32,15,16, 31. Results show that all of one-bit injected faults, 93% of two-bit faults, 98% of three bit faults, and 97% of four bit faults can be detected by the proposed substitution architecture. These are achieved at the cost of 48% in occupied area and 96% in critical path delay.