①Shool of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China; ②State Key Lab. of Info. Security, Institute of Software, Chinese Academy of Sciences, Beijing 100080, China; ③School of Science, Jinan University, Jinan 250022, China
Abstract：The four round MISTY-type and the three round dual MISTY-type transformation are optimized by replacing the first round pseudorandom permutation with XOR-universal permutation and employing identical pseudorandom permutation in the second and the third round. Thus the running time is shortened and the number of keys are saved by reducing the number of pseudorandom permutation. Hence the running cost is debased greatly. At the same time, the security remains.
2007, Vol. 29 
