基于Lai Massey变体结构的可调分组密码的设计与分析
Design and analysis of the tweakable block ciphers based on the transformation of lai massey structure

Lai Massey结构(L M结构)是分组密码中一类重要的整体结构, 任意轮的L M结构都不具备伪随机性. Vaudenay通过对L M结构做一个简单变换, 使得3轮L M变体结构具备伪随机性, 并在FOX分组密码的设计中采用此变体结构. 该文针对基于L M变体结构来设计可调分组密码进行了研究. 通过在L M变体结构的不同位置异或可调因子（tweak）, 分析了3轮基于L M变体结构设计可调分组密码的可行性. 对3轮结构提出了攻击的方法.
Lai Massey(L M) is one of the most important structures used in block ciphers. But it’s not pseudorandom with any given rounds. By a simple transform, S.Vaudenay got the transformation of L M scheme, which is preudorandom and used in FOX. This paper researched the design of tweakable blockciphers based on the transformation of L M structure. The feasibility to design block ciphers by XORing a tweak value into different places in the dataflow of the 3 round L M transformation was analyzed. The attack methods for 3 round transformation were given