In cloud computing environments, user authentication is an important security mechanism because it provides the fundamentals of authentication, authorization, and accounting （AAA）. In 2009, Wang et al. proposed an i...In cloud computing environments, user authentication is an important security mechanism because it provides the fundamentals of authentication, authorization, and accounting （AAA）. In 2009, Wang et al. proposed an identity-based （ID-based） authentication scheme to deal with the user login problem for cloud computing. However, Wang et aL＇s scheme is insecure against message alteration and impersonation attacks. Besides, their scheme has large computation costs for cloud users. Therefore, we propose a novel ID-based user authentication scheme to solve the above mentioned problems. The proposed scheme provides anonymity and security for the user who accesses different cloud servers. Compared with the related schemes, the proposed scheme has less computation cost so it is very efficient for cloud computing in practice.展开更多
With the rapid development of wireless sensor network （WSN）, the demands of limited radio frequency spectrum rise sharply, thereby dealing with the frequency assignment of WSN scientifically and efficiently becomes ...With the rapid development of wireless sensor network （WSN）, the demands of limited radio frequency spectrum rise sharply, thereby dealing with the frequency assignment of WSN scientifically and efficiently becomes a popular topic. To improve the frequency utilization rate in WSN, a spectrum management system for WSN combined with cloud computing technology should be considered. From the optimization point of view, the study of dynamic spectrum management can be divided into three kinds of methods, including Nash equilibrium, social utility maximization, and competitive economy equilibrium. In this paper, we propose a genetic algorithm based approach to allocate the power spectrum dynamically. The objective is to maximize the sum of individual Shannon utilities with the background interference and crosstalk consideration. Compared to the approach in [1], the experimental result shows better balance between efficiency and effectiveness of our approach.展开更多
文摘In cloud computing environments, user authentication is an important security mechanism because it provides the fundamentals of authentication, authorization, and accounting （AAA）. In 2009, Wang et al. proposed an identity-based （ID-based） authentication scheme to deal with the user login problem for cloud computing. However, Wang et aL＇s scheme is insecure against message alteration and impersonation attacks. Besides, their scheme has large computation costs for cloud users. Therefore, we propose a novel ID-based user authentication scheme to solve the above mentioned problems. The proposed scheme provides anonymity and security for the user who accesses different cloud servers. Compared with the related schemes, the proposed scheme has less computation cost so it is very efficient for cloud computing in practice.
文摘With the rapid development of wireless sensor network （WSN）, the demands of limited radio frequency spectrum rise sharply, thereby dealing with the frequency assignment of WSN scientifically and efficiently becomes a popular topic. To improve the frequency utilization rate in WSN, a spectrum management system for WSN combined with cloud computing technology should be considered. From the optimization point of view, the study of dynamic spectrum management can be divided into three kinds of methods, including Nash equilibrium, social utility maximization, and competitive economy equilibrium. In this paper, we propose a genetic algorithm based approach to allocate the power spectrum dynamically. The objective is to maximize the sum of individual Shannon utilities with the background interference and crosstalk consideration. Compared to the approach in [1], the experimental result shows better balance between efficiency and effectiveness of our approach.
