IoT–Cloud collaboration to establish a secure connection for lightweight devices

Internet of Things (IoT) technologies allow everyday objects including small devices in sensor networks to be capable of connecting to the Internet. Such an innovative technology can lead to positive changes in human life. However, if there is no proper security mechanism, private and sensitive data around humans can be revealed to the public Internet. In this aspect, this paper considers security issues of the IoT. In particular, we focus on various challenges in deploying Datagram Transport Layer Security (DTLS) protocol into a resource constrained environment. DTLS provides secure communication with UDP-based applications the same as TLS does for TCP-based applications. Several standard organizations such as IETF, oneM2M and OMA recommend using the DTLS as a default secure scheme for CoAP which is a new standard specified for resource-constrained environments. To find a practical way to deploy the DTLS in such a constrained IoT environments, we propose an IoT–Cloud collaboration system, where DTLS handshake delegation is the main component. We also implement and evaluate the proposed system in our real IoT testbed, where constrained devices are interconnected with each other in a multi-hop fashion. Evaluation results show that the proposed scheme dramatically reduces DTLS handshake latency, implementation code size and energy consumption.