An Implementation of Shared Symmetric Key Generation Extracted from Received Signal Strength in Vehicle to Infrastructure Communication

In this paper, we propose a key generation extracted from received signal strength (RSS) for securing vehicle-to-infrastructure (V2I) communication using Raspberry Pi embedded system equipped with 5.8 GHz radio frequency of wireless interface as well as CEN-DSRC standard for V2I. To achieve an equality of shared symmetric key between vehicle and road side unit (RSU), the probed RSS values are correlated, quantized, reconciled, and amplified. The obtained shared symmetric key is used for securing the exchange information between vehicle and RSU using symmetric encryption. We varied the speed of vehicle such that ping time interval can be varied as well on the condition of traffic both quiet and crowded. The correlation of bits key stream between vehicle and RSU is achieved by Kalman Filter over various speed of vehicle either on the condition of quiet or crowded traffic. Meanwhile, multibit quantization contributes to reduce key disagreement rate (KDR) and the remaining mismatching bits key stream are corrected by BCH error code correction, hence the key generation rate (KGR) can be increased and the shared symmetric key is able to be obtained successfully. The experimental results showed that the practicality of our proposed system whereas the total average time to generate shared symmetric key is about 11 seconds.