Abstract: A method and system for authenticating a home network device in a home network. According to the device authentication method, a public key list that includes an ID and public key information corresponding to the ID of home network devices is maintained. When an access of a joining device is received, it is requested to the joining device an ID and information relating to a public key of the joining device. The ID and the public key information are received from the joining device, and the public key list is updated by adding the received ID and public key information. The public key list before updating is transmitted to the joining device. The ID and the public key information of the joining device are transmitted to the home network devices. The joining device is a new device that joins a home network.