行動通訊之安全研究

Abstract

Recent development and the evolution of wireless communications and mobile network management have realized the applications for personal communicationservices. The name Personal Communications Services (PCS) is often used asa general term that includes various wireless accesses and personal mobilityservices. The ultimate goal is to provide mobile users to access information anywhere, any time, and in any form. In the near future, tremendous mobileusers will carry a small terminal, such as mobile phone, mobile station, handset, personal communication system, or portable computer to accessinformation through the wireless networks. With the tremendous applicationsand business opportunities provided by PCS, many issues are explored and neededto solve. Except all those the involved techniques about the wireless accessand mobile network management, security issues for the mobile communicationsare most controversial and most concerned by the users. From the views of users, the security requirements consist of user authentication, data confidentiality of communication, and privacy of user movements. Authenticationensures that service is not obtained fraudulently in order to avoid charge forusage; data confidentiality ensures that an eavesdropper cannot interceptinformation between two parties; location privacy ensures that the usersmovements cannot be obtained by third parties who are interested in their current and past locations. The goal of this study is to explore the security issues and to propose somenew or some improved protocols to meet the security requirements for mobilecommunications. In this dissertation, one new method is proposed to implementa secure digital mobile communication system. Additionally, a new key distribution scheme is designed for practical implementation in a low-cost andlow-power digital mobile communication system. The most distinguished digitalcellular system in the world is the Global System for Mobile Communications(GSM). However, there are some weaknesses of the security features in the GSM.Therefore, we propose three improved methods to enhance the security, to reducethe storage space, to eliminate the sensitive information stored in the visiteddomain, and consequently to improve the performance of the system. The merit of the proposed methods is to improve but not to alter the existing architecture ofthe system. Moreover, the Subscriber Identity Module (SIM) concept is widelyused in many mobile communication systems; some limitations and considerations of using SIM significantly reduce the availability and accessibility for thepublic in the wireless communications. the idea of using phone card for thepublic telephones is introduced for the mobile communications in this study.major technical issues for using the mobile phone card and its security considerations will be presented.