1. Research Institute for Secure Systems (RISEC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
2. Global Information and Telecommunication Institute (GITI), Waseda University, Tokyo 169-0051, Japan
3. School of Electronic and Information Engineering, Southwest University, Chongqing 400714, China
4. College of Information Engineering, Xiangtan University, Xiangtan 411105, China
5. School of Electrical and Electronics Engineering, North China Electric Power University, Beijing 102206, China