Introduction Benefits of VANET Different types of attacks and threats Requirements and challenges Security Architecture Vehicular PKI

It offers vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication

Collision Avoidance Data transmitted from a roadside infrastructure to

a vehicle could reduce the number of accidents by warn the driver.

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.

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.

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.

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

Characteristics

High mobility Dynamic topology

Large scale High density

ChallengesMaintaining routing tables is difficult

Scalability

Vehicular PKI (Public key infrastructure)

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.

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

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.

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

There are 4 parts: 1: message header; 2: the certificate; 3: message payload; 4:the signature of the signed message.

The length of signed message defined as:

The security overhead is:

The total message size:

The transmission latency of employing the certificate-based PKI scheme for VANETs can be represented as:

What is “Denial of Service” in VANET?

Attacker sends too many messages and jams the wireless channel.

If data transmission rate is 6Mbit/s, signed message format as follow:

Please calculate the transmission latency.

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:

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 [1] B. Parno and A. Perrig, Challenges in securing vehicular networks, in: Proceedings of the Workshop on Hot Topics in Networks (HotNets-IV), 2005. [2] M. Raya and Jean. Hubaux. The security of vehicular ad hoc networks. In Workshop on Security in Ad hoc and Sensor Networks (SASN), 2005.[3] IEEE P1609.2/D2 – Draft Standard for Wireless Access in Vehicular Environments – Security Services for Applications and Management Messages, November 2005.[4] J.-P. Hubaux, S. Capkun and J. Luo, The security and privacy of smart vehicles, IEEE Security andPrivacy Magazine 2(3) (2004), 49–55.[5] 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.[6] 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.