Automatic Differential Analysis of ARX Block Ciphers with Application to SPECK and LEA [chapter]

Ling Song, Zhangjie Huang, Qianqian Yang
2016 Lecture Notes in Computer Science  
In this paper, we focus on the automatic differential cryptanalysis of ARX block ciphers with respect to XOR-difference, and develop Mouha et al.'s framework for finding differential characteristics by adding a new method to construct long characteristics from short ones. The new method reduces the searching time a lot and makes it possible to search differential characteristics for ARX block ciphers with large word sizes such as n = 48, 64. What's more, we take the differential effect into
more » ... ideration and find that the differential probability increases by a factor of 4 ∼ 16 for SPECK and about 2 10 for LEA when multiple characteristics are counted in. The efficiency of our method is demonstrated by improved attacks of SPECK and LEA, which attack 1, 1, 4 and 6 more rounds of SPECK48, SPECK64, SPECK96 and SPECK128, respectively, and 2 more rounds of LEA than previous works.
doi:10.1007/978-3-319-40367-0_24 fatcat:qnnvmvvmwfhezg7heivko55mbu