  The proliferation of connected devices through Internet connectivity presents both opportunities for smart applications and risks to security and privacy. It is vital to proactively address these concerns to fully leverage the potential of the Internet of Things. IoT services where one data owner serves multiple clients, like smart city transportation, smart building management and healthcare can offer benefits but also bring cybersecurity and data privacy risks. For example, in healthcare, a hospital may collect data from medical devices and make it available to multiple clients such as researchers and pharmaceutical companies. This data can be used to improve medical treatments and research but if not protected, it can also put patients' personal information at risk. To ensure the benefits of these services, it is important to implement proper security and privacy measures. In this paper, we propose a symmetric searchable encryption scheme with dynamic updates on a database that has a single owner and multiple clients for IoT environments. Our proposed scheme supports both forward and backward privacy. Additionally, our scheme supports a decentralized storage environment in which data owners can outsource data across multiple servers or even across multiple service providers to improve security and privacy. Further, it takes a minimum amount of effort and costs to revoke a client's access to our system at any time. The performance and formal security analyses of the proposed scheme show that our scheme provides better functionality, and security and is more efficient in terms of computation and storage than the closely related works. 
A Multi-Client Searchable Encryption Scheme for IoT Environment