Improved Integral Attack on Reduced-Round Simeck

Simeck, a family of lightweight block ciphers utilizing Simon-like structure, is widely used under resource constrained environment. So far, many cryptanalysis methods have been used to attack Simeck. In this paper, we give the new results of integral cryptanalysis on reduced-round Simeck. First, the exact algebraic degree of Simeck32 is given by parallel computing, and then the 13-round theoretical integral distinguisher is proposed to attack 20-round Simeck32(64). Besides, by using the equivalent-subkey and partial-sum technology, combined with the meet-in-the-middle strategy and subkey relationship, the 22-round Simeck32(64) integral attack is first proposed based on the 15-round integral distinguisher. Furthermore, based on 18-round and 21-round integral distinguishers, the new integral attacks on 26-round Simeck48(96) and 30-round Simeck64(128) are proposed, respectively. These new attacks greatly improve the results of the previous integral attacks for Simeck.