The home network is a new IT technology environment for making an offer of convenient, safe, pleasant, and blessed lives to people, making it possible to be provided with various home network services by constructing home network infrastructure regardless of devices, time, and places. This can be done by connecting home devices based on wire and wireless communication networks, such as mobile communication, Internet, and sensor network. However, there are many risks involved, for example user privacy violations and service interference. Therefore, security service is required to block these risk elements, and user authentication is an essential component for secure home network service. It enables non-authorized persons not to use home network. In this paper, an authentication protocol for secure communications is proposed for secure home network environments. The proposed authentication protocol is designed to accept existing home networks based on public key infrastructure (PKI) and Authentication, Authorization, and Accounting (AAA), which both use Kerberos.