A memory protection about user input information for applying a password function to an interface controller inputting data about the user input information is provided to prevent the damage of the system due to hacking attack by storing user information in a memory. A user information input interface is implemented by using a data input interface security controller(A100). Inputted clear text data is encrypted and decoded. An encoding module performing a key function manager is implemented(A200). An encoding module encoding unit and an encoding module data decoding unit are interworked with the encoding module(A300). The plain text data is obtained and are not stored in the memory in the plaintext type. Data in which the encrypted data is stored in the memory or which are encrypted are transmitted to network(A500).
