# Connected Vehicles: Technology Review, State of the Art, Challenges and Opportunities
## 4 Challenges
### Privacy and Security  
High-data networks are usually prone to hackers and cyber-physical attacks. Without proper and valid protection in the CV environment, a vehicle's controllers could possibly be hacked, valuable information would be stolen, and personal data would be revealed. This raises many security and privacy concerns and imposes significant threats on automated and connected vehicles with electronic actuators. Hackers can disseminate erroneous traffic information to cause congestion or can force the vehicle to suddenly stop, jeopardizing people's lives [11; 138]. Many security breach examples have proven to be life threatening, where security breaches include unauthorized data access and attacks that may result in physical disturbance in delivering the required services [139]. As a real-life example, in 2015, a Jeep Cherokee was hijacked by hacker experts [PERSON] and [PERSON] through exploiting Uconnect, which is the CV platform integrated within the vehicle that provides entertainment, navigation, and connectivity over the Internet [138; 140]. They completely gained full control over the vehicle remotely over the cellular network and succeeded in controlling the radio station, air conditioning, and windshield wiper blades and then eventually seized control of the brakes and brought the engine to a halt. As a consequence of these security vulnerabilities, Fiat Chrysler had to recall 1.4 million Jeep Cherokee to address this issue [140]. Privacy attacks that are directed towards the vehicles' geographical location and driving habits of the drivers are among the most threatening privacy invasions. Privacy geographical location violations of vehicles enable malicious attackers to gather time series information regarding the vehicle's position. In this context, time series information can be procured from broadcast data sent by the vehicle or across transmitted data to service data-centers through cellular networks. Additionally, attackers can perform privacy breaches that target information regarding the driving behavior, which can help reveal private and personal data about the driver [141]. Whereas, security attacks may include information integrity threats. In this attack, cyber-attackers could be able to breach the network and succeed in eavesdropping or could change the signature tied to the data being transmitted over the wireless communication interface. Solutions to this type of threat include the employment of cryptographic-based techniques. Protected interchangeable key and public-key certificates are acquired by centralized trustworthy public key infrastructure (PKI) and are both needed for cryptographic-based methodologies. Data authentication is performed by PKIs, where certificates are dispatched to inform the receiver that the data is from a trusted transmitter. However, with the increasing numbers of CVs, authenticity and key exchange might undergo issues such as single points of failure and scalability problems [142]. Moreover, cryptographic-based approaches might not be feasible for attacks such as blackhole, wormhole, spamming, and others. However, the digital signature technique and bit commitment tactics might hinder their effect [143]. Many studies have been focused on the privacy and security of CVs with an emphasis on challenges that arise due to privacy and security breaches. For instance, in [142], the authors bring forward issues regarding attacks that target on-board sensors or net work attacks on wireless communication interfaces. Those attacks might greatly affect the data correctness and integrity. Even though centralized solutions exist, they are not scalable and are unable to verify the correctness of the exchanged information. The decentralized security blockchain-based technology approach is considered promising in tackling those problems. However, the presence of permissionless linear hash chains that adapt blockchain technology approaches are not feasible, as it incorporates minimum data exchange throughput and demands immense computing costs.