Secure and Efficiently Searchable IoT Communication Data Management Model: Using Blockchain as a new tool

With the rapid development of the Internet of things (IoT), more IoT devices are connected in the same network and communicate frequently for sharing data and switching instructions. So that the traditional centralized security architecture of IoT will be limited in terms of data storage space, data reliability, scalability and operating costs. In this paper, we propose a novel communication data management model based on blockchain technology. Specifically, all encrypted IoT communication data files are uploaded to public cloud server for obtaining enough storage space, but the key information extracted from these data files (called "communication logs") will be recorded in an "IoT ledger" maintained by all IoT devices. In fact, the IoT ledger is a kind of blockchain structured distributed database, which can solve the problem of data reliability, scalability and would not involve high operating costs. Besides, in order to efficiently search communication logs and not reveal any sensitive information of communication data, we design a secure search scheme over such blockchain database, the asymmetric scalar-product preserving encryption (ASPE) approach is exploited to guarantee the data security, and the two layers index improves the search efficiency. Security analysis and experiments on synthetic dataset show that our scheme is secure and efficient.