Abstract:

LiCi lightweight block cipher is a new algorithm proposed in 2017.With advantages of small structure and low energy consumption, LiCi is more suitable for resource-constrained environments such as the internet of things (IoT).In the design document of LiCi, the ability of LiCi algorithm to resist differential attack and linear attack is analyzed, but the resistance of LiCi algorithm to differential fault attack has not been discussed.According to the permutation law of each round iteration of LiCi algorithm, 32-bit key can be recovered by injecting a single bit fault into the left half of the 31st round iteration combined with its differential property.According to the key choreography scheme of the LiCi algorithm, the same differential fault attack was performed on iterations 30th, 29th, 28th, 27th and 26th round to recover all the original keys.The attack requires a total of 48-bit faults, and the computational complexity is 2³², which indicates the LiCi algorithm is difficult to resist differential fault attacks.

Key words: LiCi cipher, lightweight block cipher, differential fault attack, fault model