Current trend is being extended from the traditional Internet to the small, cheap, and low-power Internet of Things (IoT) in which the objects are being equipped with a device having computation and communication capabilities. As a result, all these objects can be connected to the Internet and have the capability to communicate among each other. This connection infrastructure among the objects would face different types of malicious attacks. Hence securing these objects is a primary goal. There are a lot of security mechanisms available today, but most of them are quite heavy in terms of computation and communication. As the IoT objects have very limited resources and mostly run on battery power, it is difficult to embed intensive computations on these resourceconstrained devices. Datagram Transport Layer Security (DTLS) protocol has been standardized to work in cohesion with the CoAP protocol to provide security. But DTLS does not fit well for multicasting, though it is a quite common need for IoT environments. Indeed there are some adaptations for DTLS protocol to function in a multicast environment, but it consumes much communication and computation resources. We propose a mechanism called S-CPABE (Segregated Ciphertext Policy Attribute-Based Encryption) based on CPABE, particularly targeting the multicast needs and tailoring to the IoT framework. The novelty of S-CPABE lies on providing equivalent security as CPABE with reduced resource requirements at the low-power end devices. This mechanism perfectly meets the needs for secure multicast in an IoT environment and consumes much less resources as compared to DTLS.
“Internet of Things” (IoT) is going to change the world in a significant way in the near future. It is going to be inherently applied to our day-to-day living and make our lives much easier. As today no one can think of a single day without Internet, a day would come when we cannot think of a single moment without the aid of IoT. Today’s Internet is mostly limited to devices like personal computers, laptops, smartphones, tablets, etc. But the idea of IoT is to have the things around us communicate among each other and the Internet. So the smallest day-today objects we regularly use, say, for example, a piece of pen, will be connected to the Internet and order a refill on its own when it is out of ink. Things will have the sufficient intelligence to interact with other things, the environment around them, and of course human beings [1–3]. A lot of research is, therefore, taking place in this field from both industry and academia. And with so many different technologies available today from Zigbee, WiFi, Bluetooth, NFC, LPWANs, and 5G cellular technologies, IoT frameworks are turned into a reality with possible applications in smart homes, smart environment, smart agriculture, etc. [4,5]. Meanwhile, there are a number of challenges of which security is the major concern. As everything gets connected to the Internet, devices get more prone to risk of threats and malicious attacks. People or other objects may post harmful contents to these networks, steal data from these devices, and make improper and illegal use of these devices . So design of the security aspects in parallel with the networking solutions is essential for the safer and popular deployment [7,8]. The next challenge is the constraint in terms of available resources on these devices. As these devices have very less memory, processing capabilities, communication bandwidth, and mostly powered by batteries, light-weight protocols are a must to conserve energy. Third, as they are small and cheap, there are billions of those devices communicating with one another.