Affiliations:  Department of Computer Science & Information Engineering, Asia University, 1500, Lioufeng Rd., Wufeng, Taichung 41354, Taiwan, R.O.C. |  Department of Medical Research, China Medical University Hospital, China Medical University, No. 91, Hsueh-Shih Road, Taichung 40402, Taiwan, R.O.C. |  Network & Multimedia Institute, Institute for Information Industry, 7F., No. 133, Sec. 4, Minsheng E. Rd., Taipei City 105, Taiwan, R.O.C. |  Graduate Institute of International Sport Affairs, National Taiwan Sport University, No. 250, Wenhua 1st Rd., Guishan, Taoyuan 33301, Taiwan, R.O.C. E-mails: [email protected], [email protected], [email protected]
Abstract: Denial-of-service (DoS) attacks against server resources exhaustion are a major security threat to the Internet. A number of defense mechanisms have been proposed against such attacks. Recently, Aura et al. proposed a solution to resist DoS attacks against an authentication protocol. However, their puzzle solution cannot guarantee that all of their clients have fair computation time to solve a puzzle. The solution may even render some clients unable to obtain the puzzle solution within the lifetime, resulting in a lack of service from the server. In this paper, a simple solution as well as an applied authentication protocol was proposed.