Protocolsthat are mostly used in automotive industry are:-CAN – Controller Area Network-LIN – Local Interconnected Network-MOST – Media Oriented System Transport-Flex Ray, etc.CAN– Controller Area NetworkThisprotocol is one of the most important serial bus system for networkingintelligent devices, emerged as the standard in-vehicle network.
Each of thedevices on the network has a CAN controller chip.CANis included in different levels with multiple networks. Example: linking thedoor units or brake controllers, passenger counting units and more.
CAN hasseveral physical layers which are classified in some aspects in CAN network.High speed CAN is the most common physical layer which allows communication upto 1Mbit/s transfer rates. Anti – lock brakes systems, engine control modulesare the typical high speed CAN devices.Low-speedCAN are implemented with two wires for communication between devices with ratesof transfer up to 125kbit/s. typical CAN low-speed devices in automobiles arecomfort devices.Singlewire CAN have communication rates up to 33kbits, typical single – wire devicesin automobiles include comfort devices such as mirror adjusters and seat.LIN– Local Interconnected networkLIN– is byte oriented communication protocol designed to support automotivenetworks in conjunction with CAN Controller Area Network.
It is cost effectivecommunication which has sensors and actuators when the features of CAN are notrequired.Themain features of LIN protocol are low cost and low speed compared to CAN – LINis used for short distance network. The LIN bus is connected between smartsensors and an ECU – Electronic Control Unit – which is a gateway with CAN bus.LIN is also a broadcast type serial network but it uses a single master andmultiple slaves. For data communication LIN uses frames. A frame consists of aheader, a response. This system of using headers and responses has a lot ofadvantages:1) The nodes can be added to the network withoutrequiring hardware or software changes in slave nodes.
2) The identifier defines the conduct of a message.3) Any number of nodes can simultaneously receive and actupon a single frame. FLEXRAYThemain purpose of Flex Ray network is to support the drive by wire systems suchas steer by wire and brake by wire. It requires good error management alongwith high transmission rates.Theprotocol of flex ray is unique time-triggered communication protocol with adual channel data rate of 10Mbps for advanced in vehicle control applications.The flex ray communication protocol is designed to provide high-speeddeterministic distributed control for advanced automotive applications.
TheFlex Ray standard is adaptable to many different types of network. Every Flex Raynetwork may be different, so each node have to be programmed with correctnetwork parameters before participating on the bus.MOST– Media Oriented Systems TransportMosthas the largest bandwidth of all the networks and it is mainly used for audio,video and telecommunication systems it is the most suitable for real time audioand video transmission applications.Mostprovides point to point audio and video data transfer with a data rate of 24.8Mbps. It support the end user applications such as radios, GPS (GlobalPositioning Systems). MOST’s physical layer is a plastic option fiber forhigher transmission rates than classical copper wires. SecurityconcernsThesecurity threat is increasing continuously because cars are gettinginterconnected with other devices and environment around.
Before the concept ofa connected car was introduced the automotive industry did not pay muchattention to cybersecurity because the attackers required physical access toperform attack.Todaywe have cars with multiple connections to other network including connection tointernet.Figure2.3Figure 2.3 shows all the additional services that the connected carwill have in the future.
Car2Cloud technology represents all internal servicesavailable because of the existence of Internet connections. THEFOUR MAIN DIFFICULTIES IN SECURING THE CONNECTED CAR ARE THE FOLLOWING AREAS:1. Over the air updates. (OTA). The connected cars arevery similar to computers, since they are having very complex softwarearchitecture and a lot of lot of applications which help enabling the newfeatures. These software needs to be updated to with new bug fixes or securitypatches to prevent discovered vulnerabilities.
The updates could be verycritical and sometimes dangerous for the safety of the driver and passengers ifnot installed on time, and these create problems to automotive industry.2. Low computational power. The computational power of vehicles is low.This happens because of long life cycle of the vehicles and the conditions ofthe environment. To the attackers this is one advantage because they canleverage the power of stronger computers. As the vehicles gets older, the moreadvanced technologies will be developed comparing to the cars production yearmakes it even easier to exploit.3.
Difficult to monitor. Because the car is not all thetime connected to the internet it is difficult to monitor the status of theautomotive electronics.4. Cost – one of the major difficulties is the cost ofmaking the software of the vehicle to be secure. Companies would need to employmore people and they would need to change their entire development process inorder to incorporate security from the very beginning.5. No safety without security – only one infected car onthe road is a potential hazard for the surrounding vehicles, and each securityvulnerability exposes new safety issues.
THREATMODELING OF THE CONNECTED CARThe method which was invented by Intel called Threat Agent RiskAssessment (TARA) has in its main focus the attackers. It is based ondescriptions of threat agents and their appropriate attributes such asmotivation, objective, skill, resources, attach methods and attack surface. . The method is not time-consuming and theknowledge required, and input information can be accessed which one of thereasons why it was chosen for the threat is modeling in this case. It is alsovery adaptable and can be applied to various industries such as the