Fuente: Wipo "IOT" The present invention relates to a security technology for a home network system, and more particularly, to a data security method of a home network system, which is applied with an asymmetric algorithm and a symmetric key algorithm for interactive authentication and data encryption. To this end, the home network system of the present invention comprises an IoT server and an IoT terminal in which data security is implemented. The IoT server and the IoT terminal exchange a public key with each other, the IoT terminal encrypts terminal information and a terminal random number with a public key of a server and transmits the same to the IoT server, and the IoT server decrypts the terminal information and the terminal random number with a private key of the server, and then encrypts the terminal information and a server random number with a public key of a terminal to transmit the same to the IoT terminal. Also, the IoT terminal decrypts the terminal information and the server random number with a private key of the terminal, and the IoT server and the IoT terminal separately generate a symmetric key using the terminal random number and the server random number. Therefore, the home network system with enhanced security can be provided. COPYRIGHT KIPO 2023