Symmetric Key-Based Secure Storage and Retrieval of IoT Data on a Semi-trusted Cloud Server

The storage of data in the cloud is critical for business and private users to protect their assets from any physically accessible and easily breakable hard disk. An important issue for cloud services is the privacy of the stored data at risk of a breach following an attack or the possibility that the cloud service provider may be tempted to sell data under their control to third parties. Therefore, we need to ensure that data we share or store in the cloud are totally protected from any intentional or unintentional security breach, whether it is related to confidentiality, integrity or authentication. In this paper, we consider the scenario of data coming from small and constrained devices to be stored in the cloud server, whereas the device owner is responsible for the authorization and management of the access control of the data requestors. After approval of the request, the owner provides a re-encryption key to the cloud server in order to make the data readable for the requestor. At no stage in the process, the server is able to retrieve the original sensor data. To guarantee optimal efficiency at the sensors’ side, the operations in the scheme are limited to symmetric key based mechanisms like xoring and encryption, as opposed to existing work where re-encryption algorithms rely on public key-based operations.