Certificate-Based Securing Vehicular Networks Instructor: Ivan Stojmenovic Presenter: Guan, Wen #6582156 email@example.com
Outline • Introduction • Benefits of VANET • Different types of attacks and threats • Requirements and challenges • Security Architecture • Vehicular PKI
Vehicular ad-hoc network(VANET) • It offers vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication
Benefits of VANET • Collision Avoidance Data transmitted from a roadside infrastructure to a vehicle could reduce the number of accidents by warn the driver.
Benefits of VANET • Cooperative Driving Many accidents come from the lack of collaboration between drivers. We can prevent many accidents if we provide more information to drivers. • Trafﬁc Optimization Vehicles could detect if the number of neighboring vehicles is too many and their avenges speed is too slow, and then relay this information to vehicles approaching the location.
Different types of attacks and threats • Bogus information attack Adversaries send bogus information in the VENET so as to influence the decisions of other drivers. • e.g. Greedy Drivers Attacker may interfere other drivers by report a non-exist jamming for a better driving condition.
Different types of attacks and threats • Disrupt the VANET (e.g. Denial of Service) • Attacker sends too many messages and jams the wireless channel. • Vehicle Tracking • Masquerading • Active attack attempts pretends to be another driver by using fake identities and can be provoked by malicious objectives.
Requirements and challenges • Time sensitivity Vehicles move at a fast rate. • Scalability: Extremely large amount of network entities • Adaptive privacy Diverse privacy degrees. Users can choose their own privacy degree. • Real-time response
Requirements and challenges Challenges Maintaining routing tables is difficult Scalability • Characteristics • High mobility • Dynamic topology • Large scale • High density
Security Architecture • Vehicular PKI (Public key infrastructure)
Security Hardware • Event Data Recorder (EDR): provides tamper-proof storage. Main responsible: record the vehicle’s critical data. • Tamper-Proof Device (TPD): possesses cryptographic processing capabilities. Main responsible: 1: store cryptographic material. 2: perform cryptographic procedure. 3: sign and verify safety messages.
Vehicular Public Key Infrastructure • Certificate Authorities (CAs) • CA issues certified public/private key pairs to vehicles. • The different CAs should be cross-certified. Vehicles from different countries or manufacturers should verify each other. • Require too much storage space
Authentication • To authenticate each other, vehicles will sign each message with their private key and attach the corresponding certificate. • When another vehicle receives this message, it verifies the key used to sign the message and once this is done correctly, it verifies the message.
Certificate Revocation • The most common way to revoke certificates is the distribution of CRLs (Certificate Revocation Lists) that contain the most recently revoked certificates; CRLs are provided when infrastructure is available. • But there are several drawbacks to this approach. • 1、CRLs can be very long due to the large number of vehicles and their high mobility. • 2、the short lifetime of certificates still creates a vulnerability window. • 3、the availability of an infrastructure will not be pervasive, especially in the first years of deployment. • Solution： Revocation Protocol of the Tamper-Proof Device
Signed message format • There are 4 parts: • 1: message header; • 2: the certificate; • 3: message payload; • 4:the signature of the signed message.
Signed message format • The length of signed message defined as: • The security overhead is: • The total message size:
Transmission Latency • The transmission latency of employing the certificate-based PKI scheme for VANETs can be represented as:
Question 1 • What is “Denial of Service” in VANET? • Attacker sends too many messages and jams the wireless channel.
Question 2 • If data transmission rate is 6Mbit/s, signed message format as follow: • Please calculate the transmission latency.
Question 2 • The transmission latency of employing the certificate-based PKI scheme for VANETs can be represented as: = 2008 bits = (2+67) x 8 = 552 bits The transmission latency is:
Question 3 • What is the process of Vehicular PKI. • To authenticate each other, vehicles will add digital signature at each message, this digital signature was generated by encrypted hash value of message using the private key. Thus, after another vehicle receives this message, it verifies the key used to sign the message. Only if two values are equal, it verifies the message.
Bibliography  B. Parno and A. Perrig, Challenges in securing vehicular networks, in: Proceedings of the Workshop on Hot Topics in Networks (HotNets-IV), 2005.  M. Raya and Jean. Hubaux. The security of vehicular ad hoc networks. In Workshop on Security in Ad hoc and Sensor Networks (SASN), 2005.  IEEE P1609.2/D2 – Draft Standard for Wireless Access in Vehicular Environments – Security Services for Applications and Management Messages, November 2005.  J.-P. Hubaux, S. Capkun and J. Luo, The security and privacy of smart vehicles, IEEE Security andPrivacy Magazine 2(3) (2004), 49–55.  D. Jungels, M. Raya, I. Aad and J.-P. Hubaux, Certiﬁcate revocation in vehicular ad hoc networks, Technical Report LCA-REPORT-2006-006, EPFL, 2006.  X. Lin et al., “GSIS: A Secure and Privacy-Preserving Protocol for Vehicular Communications,” IEEE Trans. Vehic. Tech., vol. 56, no. 6, Nov. 2007, pp. 3442–56.