19-01-2013, 12:35 PM
An Identity-Based Security System for User Privacy in Vehicular Ad Hoc Networks
An Identity-Based Security.pdf (Size: 878.77 KB / Downloads: 33)
Abstract
Vehicular ad hoc network (VANET) can offer various services and benefits to users and thus deserves deployment effort.
Attacking and misusing such network could cause destructive consequences. It is therefore necessary to integrate security
requirements into the design of VANETs and defend VANET systems against misbehavior, in order to ensure correct and smooth
operations of the network. In this paper, we propose a security system for VANETs to achieve privacy desired by vehicles and
traceability required by law enforcement authorities, in addition to satisfying fundamental security requirements including
authentication, nonrepudiation, message integrity, and confidentiality. Moreover, we propose a privacy-preserving defense technique
for network authorities to handle misbehavior in VANET access, considering the challenge that privacy provides avenue for
misbehavior. The proposed system employs an identity-based cryptosystem where certificates are not needed for authentication. We
show the fulfillment and feasibility of our system with respect to the security goals and efficiency.
INTRODUCTION
VEHICULAR ad hoc networks (VANETs) are receiving
increasing attentions from academia and deployment
efforts from industry, due to the various applications and
potential tremendous benefits they offer for future VANET
users. Safety information exchange enables life-critical
applications, such as the alerting functionality during
intersection traversing and lane merging, and thus, plays
a key role in VANET applications [1], [2], [3], [4], [5]. Valueadded
services can enhance drivers’ traveling experience by
providing convenient Internet access, navigation, toll
payment services, etc. [1], [3], [4], [5]. Other applications
are also possible including different warning messages for
congestion avoidance, detour notification, road conditions
(e.g., slippery), etc., and alarm signals disseminated by
emergency vehicles (e.g., ambulance) for road clearance [1],
[2], [3], [5], [6]. The attractive features of VANETs inevitably
incur higher risks if such networks do not take security into
account prior to deployment. For instance, if the safety
messages are modified, discarded, or delayed either
intentionally or due to hardware malfunctioning, serious
consequences such as injuries and even deaths may occur.
This necessitates and urges the development of a functional,
reliable, and efficient security architecture before all other
implementation aspects of VANETs.
RELATED WORK
There is a large body of research work related to the security
and privacy in VANETs. The most related works are on the
design of privacy-preserving schemes. Raya and Hubaux [3]
investigated the privacy issue by proposing a pseudonymbased
approach using anonymous public keys and the public
key infrastructure (PKI), where the public key certificate is
needed, giving rise to extra communication and storage
overhead. The authors also proposed three credential
revocation protocols tailored for VANETs, namely RTPD,
RC2RL, and DRP [11], considering that the certificate
revocation list (CRL) needs to be distributed across the
entire network in a timely manner. All the three protocols
seem to work well under conventional public key infrastructure
(PKI). However, the authors also proposed to use
frequently updated anonymous public keys to fulfill users’
requirement on identity and location privacy. If this privacy
preserving technique is used in conjunction withRC2RLand
DRP, the CRL produced by the trusted authority will become
huge in size, rendering the revocation protocols highly
inefficient.
Proof of Knowledge
A proof of knowledge is an interactive proof where the
prover convinces the verifier of the validity of a statement.
In the case of a zero knowledge proof of knowledge, the
above interactive proof is carried out without the prover
revealing any information used to prove the statement. Let
G be a cyclic group with generator g where solving the
discrete logarithm is intractable. G is of prime order p. One
can prove the knowledge of the discrete logarithm x 2 Zp
with respect to y in base g as PKfðxÞ : y ¼ gxg, which is the
so-called -protocol of three move structure: commitment,
challenge, and response. Schnorr [24] first provided a
construction for the -protocol. The threshold authentication
technique used in this paper as the defense against
misbehavior is based on the -protocol for zero knowledge
proof. The proof of knowledge techniques are mainly used
for the threshold-authentication-based defense scheme.
Threshold Authentication-Based Defense
Scheme
When misbehavior occurs during network access, network
authorities require the revocation of misbehaving users and
should not be able to arbitrarily trace honest users. It can be
achieved only by defense schemes that offer privacypreserving
and traceability features. Furthermore, the key
reason for adopting the threshold authentication technique
is the capability to tolerate certain misbehavior due to the
flexible threshold, in addition to the privacy and traceability
guarantees. This functionality cannot be provided by the
pseudonym-based approach. Consider malfunctioning vehicles
as an example of nonmalicious misbehavior that
should be tolerated to certain extent. Malfunctioning and
intentional (or malicious) misbehavior are difficult to
distinguish, which would require additional software
installed in vehicles and RSUs to analyze the behavior of
the message sender and to reach a decision. As a result, it is
not an easy task to apply defense schemes differently for
malfunctioning and “real” misbehavior. This is the reason
that threshold authentication is employed in our defense
scheme, where misbehavior can be tolerated as long as the
number of times it occurs is less than the specified
threshold.
CONCLUSION AND FUTURE WORK
We have presented the VANET security system mainly
achieving privacy, traceability, nonframeability, andprivacypreserving
defense against misbehavior. These functionalities
are realized by the pseudonym-based technique, the
threshold signature, and the threshold authentication based
defense scheme. The ID-based cryptosystem facilitates us to
design communication and storage efficient schemes.
Through security and efficiency analysis, our system is
shown to satisfy the predefined security objectives and
desirable efficiencies. Our future work consists of simulating
the proposed security system and experimenting it in real
VANET settings.