Security threats and their countermeasures of mobile portable computing devices in ubiquitous computing environments

Security has been more crucial issue as targets of attacker are wide ranges from personal information to various things in ubiquitous computing environments. Portable computing devices such as cellular phone, PDA, and smart phone in such conditions have been exposured under security threats, which cause attacker to exploit malicious code and modification of storied data. In this paper we present security threats and their countermeasures in technical, manageable, and physical aspect of mobile portable computing devices. We believe that this paper will contributes on initiating a research on security issues of mobile portable computing devices and provide users with guidance to keep their information safe in mobile communication environments.