Light-Weight Cryptographic Techniques For Automotive Cyber Physical Systems

In recent years,with the rapid expansion of economy and the increasing growth of population,the number of cars has increased rapidly.Even though cars provide convenience for people,they bring serious challenges to the road traffic system,such as traffic jams,frequent accidents and so on.All these challenges form a serious threat to people's lives and property.Intelligent Transportation System(ITS)are set up,aiming to offer promising applications through the close cooperation of vehicles,roads and drivers to improve transport efficiency,effectively alleviate traffic congestion,reduce the incidence of traffic accidents,reduce energy consumption as well as to reduce environmental pollution.As the core foundation of ITS,vehicular ad-hoc networks(VANETs)have attracted wide attention from the government,automobile industry and researchers.The VANETs construct a large-scale mobile multi-hop network among On Board Units(OBUs),Road Side units(RSUs)and Certificate Authority(CA)to realize wireless communication between vehicles and RSUs in a high-speed mobile environment by exchanging security information packets with each other to alleviate the increasingly serious traffic problems.However,VANET has the features of large-scale network,open wireless channel and predictable mobile trajectory etc.which makes it susceptible to numerous attacks and may expose vehicles' privacy information.Therefore,the security of vehicular ad-hoc network transmission and protection of vehicle privacy has become the main research direction of researchers.VANETs have some unique characteristics such as high mobility,dynamic network topology and non-tolerate to delay in communication etc.which makes traditional cryptographic algorithms such as elliptic curve cryptography unfit for the future automotive applications.In view of the above problems,this thesis mainly focusses on the lightweight cryptographic protocol for automotive Cyber Physical Systems(CPS)and the main contributions of this thesis are as follows:(1)An enhanced Hopper-Blum(HB)authentication protocol which integrates the physical layer key generation method is proposed to reduce information leakage.The scheme uses mismatched bits as induced noise to solve the Learning Parity with Noise(LPN)problem.The proposed Hopper-Blum based Physical Layer(HB-PL)authentication method tries to reduce the amount of data leaked through the common channel.In addition,the scheme is efficient and simple,which helps to decrease the number of messages exchanged in the authentication process.The experimental results show that,compared with the existing authentication technologies,this scheme can generate keys with stronger security and higher performance.(2)Multiple Antenna based Hopper-Blum(MA-HB)scheme is proposed by integrating the currently used Hopper-Blum(HB)protocol with multiple antennas design to authenticate the authorized person.The MA-HB scheme proposed for PKES uses multiple antennas wherein an authorized key passes through multiple vicinities to allow driver to access and start the car.Application of multiple antennas to the currently developed cryptographic algorithms opens a new approach for researchers to improve security of RFID based systems.The simulation results show that the security function is improved when considering the efficiency constraints.(3)A key distribution mechanism for vehicular networks based on Kirchhoff s law-Johnson Noise(KLJN)is proposed,which increases the bit generation rate by increasing the number of resistors in the closed circuit.The KLJN scheme eliminates the verification of digital certificates by using an unconditional secure key exchange mechanism to assign secret keys to the roadside units.In order to reduce the minimum limit for life time of KLJN key,the original KLJN key exchange circuit is modified.Simulation results illustrate the improvement in security functionality while keeping in view the efficiency constraints.