Secure mobile subscription of sensor-encrypted data

In an end-to-end encryption model for a wireless sensor network (WSN), the network control center preloads encryption and decryption keys to the sensor nodes and the subscribers respectively, such that a subscriber can use a mobile device in the deployment field to decrypt the sensed data encrypted by the more resource-constrained sensor nodes. This paper proposes SMS-SED, a provably secure yet practically efficient key assignment system featuring a discrete time-based access control, to better support a business model where the sensors deployer rents the WSN to customers who desires a higher flexibility beyond subscribing to strictly consecutive periods. In SMS-SED, a node or a mobile device stores a secret key of size independent of the total number of sensor nodes and time periods. We evaluated the feasibility of deploying 2000 nodes for 4096 time periods at 1024-bit of security as a case study, studied the trade off of increasing the storage requirement of a node to significantly reduce its computation time, and provided formal security argument in the random oracle model.