Chien-Nan Wu

Learn More
Recently, Hwang, Shiau and Lai proposed an efficient authentication key exchange protocol to decrease the computation cost of the Harn-Lin improved protocol. However, the Hawang-Shiau-Lai protocol cannot withstand the modification attack. Therefore, this paper will propose an improved protocol to enhance the security of the Hwang-Shiau-Lai protocol. The(More)
Mobile location technologies have drawn much attention to cope with the mass demands of wireless communication services. Although clustering spatial data is viewed as an effective way to access the objects located in a physical space, little has been done in estimating mobile location. In wireless communication, one of the main problems with accurate(More)
For the mass demands of wireless communication services, the mobile location technologies have drawn much attention around the world. In wireless communication, one of the main problems with accurate location is nonline of sight (NLoS) propagation. To solve the problem, we present a new location algorithm with clustering technology by utilizing the(More)
With the rapid development of electronic commerce, digital credentials are used with increasing frequency. Today users employing digital credentials not only complete the identity authentication process and obtain service, but also attach importance to their anonymity with the concept of privacy protection that is being rapidly developed. For this reason,(More)
A micropayment scheme provides an efficient way for electronic payment with small face value. It is suitable for environments that require frequent transactions such as pay-per-view movie, video streaming, etc. Recent researches on micropayment introduce additional properties such as user anonymity and fairness in micropayments. However, existing schemes(More)
Cloud computing has been developed rapidly in recent years, and offers novel concepts and innovations in computer use. The applications of cloud computing are that people can put their data on cloud and also can designate a proxy to help them to execute a number of tasks in certain situations. The proxy re-encryption which is a cryptographic primitive has(More)
In 1999, Tan and Zhu proposed a remote password authentication scheme that is the first remote login scheme using smart cards based on cross product of matrixes. The scheme is efficient and flexible as compared with other matrix-based remote authentication schemes. However, Chien, Jan, and Tseng have shown that an attacker can impersonate a legitimate user(More)