Abstract
Vehicle sensors are continuously observing the state of the vehicle, collecting and transmitting data from/to surrounding road users. The sensors data are then processed and stored in an in-vehicle sensor database in the form of records. These records can be accessed and shared by other vehicles or road side units with the aim to improve road safety. However, these records may contain a very sensitive information, such as vehicles' identifiers and location. This information requires extraordinary protection to ensure privacy and confidentiality of the vehicle users. In this article, we propose a secure oblivious transfer protocol with hidden access control and outsourced decryption from deterministic finite automata (DFA)-based functional encryption (HACOT-DFA). To reduce the computational costs for users with limited resources, we securely offload the heavy decryption overhead on the user side to an untrusted cloud server. Then, we experimentally compare our HACOT-DFA protocol against existing HACOT protocols in three different platform settings: the smartphone, the desktop personal computer, and the embedded device Raspberry Pi. The analyses demonstrate that the proposed HACOT-DFA protocol is more efficient and computationally stable than previous work. Our security proof holds in the standard model using a dual-system encryption approach.