Robust FSMs for cryptographic devices resilient to strong fault injection attacks
Zhen Wang, Mark G. Karpovsky · 2010
The security of the cryptographic device may be compromised if the FSM of the system is not properly protected. FSM protection architectures based on linear codes cannot provide a guaranteed level of protection under the assumption of a strong attack model. In this paper, we propose secure FSM architectures based on the idea of randomly selecting one code from a set of codes for each encoding and decoding operation. Assuming that the attacker is able to inject specific error patterns, randomly selecting one code from L codes as described in the paper can reduce the chance for the attacker to conduct a successful attack by a factor of L. The proposed techniques can achieve much higher security level than architectures based on linear codes with reasonable hardware overhead for cryptography applications (120% - 130% for the protection of the FSM for the Montgomery ladder algorithm). The security level of the proposed architectures can be increased by increasing L and the number of information bits k of the codes.