Method for managing smart home environment, method for joining smart home environment and method for connecting communication session with smart device

A method of managing a smart-home environment by a server, the method comprising:

• receiving identification information and a password of an unauthenticated smart device from a user terminal;
• generating a new group key based on the received identification information of the unauthenticated smart device and identification information of authenticated smart devices;
• transmitting the new group key to the authenticated smart devices by encrypting the new group key with a previous group key without authentication for the authenticated smart devices;
• receiving identification information and a password from the unauthenticated smart device;
• comparing the identification information and the password received from the unauthenticated smart device with the identification information and the password received from the user terminal;
• and
• transmitting the new group key to the unauthenticated smart device according to a result of the comparison,
• wherein the previous group key is commonly used in the smart-home environment including the authenticated smart devices before the new group key is generated,
• receiving identification information, a password, a request message, and a random number of the user terminal from the user terminal;
• authenticating the user terminal by comparing pre-stored identification information and password of the user terminal with the identification information and the password of the user terminal received from the user terminal;
• and
• when the user terminal is authenticated, transmitting the request message and the random number to smart devices that are members of the smart-home in such a manner that the user terminal and a session between the smart devices that are members of the smart-home are connected to each other.