One time password unified authentification system and constructing method thereof

A unified one time password authentication system and a method for constructing the same are provided to use efficiently overall functions of a service system and to maximize user convenience between various service servers and a mobile terminal under a unified wired/wireless environment. A unified OTP(One Time Password) authentication system includes a mobile terminal(100), plural service servers(200), a unified OTP server(300) and an application management server(400). The mobile terminal mounts an OTP client(110). The plural service servers provides various kinds of content and services for the mobile terminal and mount OTP generating modules(210) having different OPT generating processes. The unified OTP server provides a single solution for the plural service servers to install the same OTP generation module, gives different seeds to the service servers for making the service servers have different OPT generation processes, and provides a virtual machine based OTP client for the mobile terminal to generate the OTP matched with the service server. The application management server provides an applet based OPT client for the mobile terminal.