Improved differential fault analysis on lightweight block cipher LBlock for wireless sensor networks

LBlock is a 64-bit lightweight block cipher which can be implemented in both constrained hardware environments, such as wireless sensor network, and software platforms. In this paper, we study the security of LBlock against a differential fault analysis. Based on a random nibble fault model, we propose two versions of the attack on LBlock. In the first attack, we inject random nibble faults to the input register of round 29. As a result, it can recover the secret key of LBlock using an exhaustive search of 2²⁵ and five random nibble fault injections on average. This attack can be simulated on a general PC within a few seconds. In the case of second attack, random nibble faults are induced to the input register of round 30. This attack can recover the secret key of LBlock using an exhaustive search of 230 and seven random nibble fault injection on average. This attack can be simulated on a general PC within 1 h. These results are superior to known differential fault analytic result on LBlock.