Abstract
With the growth of Internet of Things (IoT), users develop many different IoT applications in web cloud platforms. However, cloud-based web services do not usually apply to the constrained networks because of HyperText Transfer Protocol (HTTP). In addition, distributed mechanisms to achieve identity authentication or data confidentiality are becoming more and more important when the number of devices located in IoT networks increases. The paper proposes the IoT Framework based on IoTtalk. IoTtalk is a web platform for users to quickly develop IoT applications. To enhance the applicability of IoTtalk in IoT networks and support identity authentication as well as data confidentiality, we introduce CoAP-based IoT Proxy and smart contract-based IoT Chain respectively. The IoT Proxy promotes the applicability of IoTtalk in IoT networks through the Constrained Application Protocol (CoAP). The IoT Chain provides identity authentication as well as data confidentiality to IoTtalk through the blockchain and the smart contract. Our experiments show that the IoT Framework promotes the security of the IoTtalk and keeps the performance of IoTtalk.