by identifying the possible attacker and dropping his
messages. In this way, the algorithm works as a fire-
wall by isolating the possible malicious vehicle.
The authors of (Leinm
¨
uller et al., 2010) present
a solution to protect VANET communications from
roadside attackers. In this scenario, the attacker is
someone located next to a road and it is a vehicle that
generates messages that are not distinguishable from
the other cars. In this way, the attacker is able to send
fake messages on the net to influence the behaviour of
drivers on the road. Even though the problem we face
is similar, we focus on internal attackers, i.e., vehicles
that send too much messages to reduce the availability
of the VANET. Furthermore, the approach they pro-
posed in based on the distance of the attacker while
we propose an algorithm based on reputation of a ve-
hicle.
Being more general, literature about reputation
system in peer-to-peer network can be also consid-
ered. As an example, the work in (Stakhanova et al.,
2004) presents a fully decentralized approach to com-
pute the reputation of peers based on the traffic be-
tween a node and its peers, independently of these
peers willingness to cooperate in calculation of their
reputation. A part form the different network commu-
nication, the main difference between this work and
the one we propose is the final goal: in (Stakhanova
et al., 2004) they want to find the optimal peers for the
communication, while we want to identify the possi-
ble attacker and prevent it to badly affect the commu-
nication among all the other nodes in the VANET.
6 CONCLUSION AND FUTURE
WORK
Automotive systems present many security challenges
that depend on several factors such as, the heterogene-
ity of embedded systems and communication tech-
nologies to make vehicle connected. In this paper
we focus on Vehicle to Vehicle communication and,
in particular, we provide a reputation based algorithm
able to evaluate whether a vehicle behaves as an at-
tacker. As a result we are able to verify if a DoS attack
happens and mitigate it to preserve the availability of
vehicle communications for safety communication.
As ongoing work, we are simulating the perfor-
mance of the proposed algorithm to evaluate its effi-
ciency and feasibility in the verification and valida-
tion of both V2V and V2X communications. In the
future, we aim at enhancing our proposal to overcome
other security issues, such as data integrity and con-
fidentiality. We will refine our algorithm to prevent
malicious vehicles, for instance, from sharing wrong
identity information and creating messages that look
like forwarded messages but are actually newly cre-
ated ones. Furthermore, we would like to consider
the possibility that a malicious vehicle tries to attack
the infrastructure by, for instance, uploading fake ob-
servation tables to the server to arbitrarily change the
reputation scores The ultimate goal will be the deeply
analysis of the impact of the proposed solution on
safety aspects, such as, how much we are able to im-
prove the traffic on a road and to reduce traffic jam.
ACKNOWLEDGEMENT
Work partially supported by the H2020-MSCA-ITN-
2015-NeCS 675320.
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