each vehicle. Pseudonym authentication, credential/identity management and revocation of compromised modules are assumed to take place at certification authorities instantiated at the roadside infrastructure.

 

Top challenges and existing solutions

Adapting to Future Platforms. According to Kargl et al., 21 in order to have a compatible architecture that can adapt to the ever-growing future vehicular technologies, integration of the security and privacy features should be based on the hooking concept where interlayer proxies are placed at several points of the communication stack. This way, only these intermediate layers must be configured if the security features are to be migrated to new platforms. The SeVeCom project implemented in-vehicle security by introducing a firewall that controls the data flow to and from the vehicle, and is also devising an intrusion detection system (IDS) that constantly monitors the data flow and detects attacks/ anomalies or denies system access in real time.

Secure Beaconing. Safety/Secure beaconing in which periodic beacon messages are digitally signed and certified may become a challenge as the security communication will infer an overhead due to signature generation and certificates attached to each packet. The performance of VAN security can be enhanced by utilizing compact certificates, in which not all messages get certificate attachments. 21 Instead, signatures and certificates are cached, removed in certain cases, or only generated after every few successive beacons. However, context-adaptive message dissemination, gossiping, and data aggregation are also interesting techniques that can be considered for vehicular systems.

Privacy Issues. Privacy protection in VAN mostly deals with providing anonymity for vehicle message transmissions such that vehicle/user’s private information, especially location may not be easily traced. SeVeCom has integrated privacy features in VAN by making use of pseudonyms and frequently changing these pseudonyms, making vehicle tracking nontrivial. 21 Since vehicles may be fully tracked even be-

integration of
security and
privacy features
should be based
on the hooking
concept where
interlayer proxies
are placed
at several
points of the
communication
stack.

tween pseudonym changes, challenges lie in devising new mechanisms that support privacy in VAN. Some techniques rely on group signatures where a number of vehicles in near proximity that are traveling with almost the same velocity can be grouped together. In the case of grouping, only one signature will be generated for the whole group, thus enhancing the group member vehicles’ anonymity and privacy. 36 However, such techniques may not be efficient for actual deployment, and hence other techniques such as hybrid solutions to VAN privacy are required and remain as current ongoing research efforts.

Real-world Simulation. Many works have simulated the performance and security features of VAN by synthetically forming a VAN network topology. Real-world scenarios of a potentially large network of vehicles consisting of hundreds of vehicles in large geographical areas need to be emulated to capture the actual performance of VAN, especially under certain attacks (for example, overloading or jamming), and/or other type of congestions. The work in Haas et al. 15 simulated a relatively large and dense network of vehicles under accident-like scenarios, and reported how VAN would perform in terms of speed of the vehicles, message reception, and so on. Other real-life scenarios should be integrated within the simulations to reflect the actual advantages or disadvantages of various VAN techniques.

Securing Vehicle Access Control and Theft Prevention. Security and privacy of VAN deals with secure and private communication such as preventing unauthorized vehicle access, attacks against in-vehicle control systems, and attacks over diagnostic onboard units and sensors (for example, exploiting tire pressure monitoring). It should also provide anti-theft features for vehicles. Though techniques such as a remote kill switch (that remotely shuts off the engine in case of vehicle theft) have been implemented ( www.3built.com), vehicle theft prevention still remains as a security challenge of VAN. Additionally, as there are techniques to duplicate real keys from only an image, 25 it is clear that security concerns should be taken more seriously into consideration.