Abstract:

Based on a new symbol differential representation,an automated search technique is presented,which can search out the optimal iterative differential mode of the block cipher with FeistelSP structure.Selection of an appropriate mode can help find out all of the best iterative differential paths.The proposed method can not only greatly reduce the computational complexity,but also construct several rounds of optimal differential paths and find other unknown results. Based on the lightweight block cipher MIBS with automated search tools,the third and fourth optimaliterative differential paths of MIBS are found out, and the probabilities are 2-20 and 2-26 respectively.In addition,all the optimal iterative differential paths that meet the conditions are searched out.Key words:  

Key words: Feistel-SP;MIBS;automated search;symbol differential;iterative differential