Development of certificate based secure communication for mobility and connectivity protocol

Some Internet of Things (IoT) devices for smart lock systems, home management systems have been released in recent years. Almost all services employ a client-server model because direct communication among these devices is difficult due to the Network Address Port Translation (NAPT) mechanism. Recently, some new ideas such as a fog computing and an edge computing have been proposed to create a distributed service. A direct communication is suitable for these ideas because each service devices should communicate with each other to realize a distributed processing. The authors have been developed Network Traversal with Mobility (NTMobile) which is a protocol for realizing a direct communication between devices and a secure communication. This paper extends the secure communication mechanism of NTMobile to realize a direct encryption key exchange mechanism between devices by employing the technology of Public Key Infrastructure (PKI). The developed protocol can provide a mutual authentication mechanism and secure encryption key exchange mechanism among devices. The evaluation results show that the overhead of the developed implementation is not large in practical services comparing to the conventional key exchange mechanism of NTMobile.