734 IEEE INTERNET OF THINGS JOURNAL, VOL. 6, NO. 1, FEBRUARY 2019
Reliable and Secure Vehicular Fog
Service Provision
Yingying Yao, Xiaolin Chang , Member, IEEE, Jelena Miši
´
c, Fellow, IEEE,
and Vojislav B. Miši
´
c
, Senior Member, IEEE
Abstract—Vehicular fog computing (VFC) complements
vehicular cloud computing as a promising solution for
accommodating the surge of mobile traffic and reducing latency.
This paper considers vehicular fog service (VFS) provided by
a vehicular fog (VF), which is formed on-the-fly by integrat-
ing computing and storage resources of parked vehicles. VF
dynamicity, due to vehicles’ random arrivals and departures,
poses a number of challenges for reliable and secure VFS
provision to client vehicles. We propose a novel mechanism
which consists of a VF construction method and a VFS access
method to ensure VFS reliability and security without sacri-
ficing performance. The reliability and security of VFS under
our mechanism are discussed in detail. Moreover, we investigate
the impact of the proposed mechanism on VF throughput and
show that the mechanism is lightweight enough to be used in the
latency-sensitive VFC.
Index Terms—Quality of service, reliability, security, vehicular
fog service (VFS).
I. INTRODUCTION
R
ECENT years witnessed rapid development and deploy-
ment of intelligent units in vehicles such as on-board
computer and sensing devices. These units on a vehicle have
significant capacity and then could meet the communica-
tion, computation, and storage requirements of applications
installed on this vehicle during its driving. Meanwhile, there
are still abundant onboard capabilities. In order to make
full use of the underutilized resources in vehicles, vehicular
cloud (VC) was put forward [1]–[3] and it has attracted much
attention from both academia and industry, including produc-
tion cloud services such as IBM Cloud that has been offered
to connected vehicles [4].
However, VC computing (VCC) suffers some serious limi-
tations, such as it is not fit for emerging time-critical safety or
infotainment services which have much stricter latency con-
straints. Gartner reported that there will be about 250 million
“connected” cars on road by 2020 [5], further highlight-
ing the necessity of reliable services for latency-sensitive
Manuscript received April 16, 2018; revised June 14, 2018; accepted
July 3, 2018. Date of publication July 13, 2018; date of current version
February 25, 2019. The work of X. Chang was supported by the NSF of
China under Grant 61572066. The work of J. Miši
´
candV.B.Miši
´
c was sup-
ported by the National Science and Engineering Research Council of Canada
through Discovery grants. (Corresponding author: Xiaolin Chang.)
Y. Yao and X. Chang are with the Beijing Key Laboratory of Security
and Privacy in Intelligent Transportation, Beijing Jiaotong University, Beijing
100044, China (e-mail: yingyingyao@bjtu.edu.cn; xlchang@bjtu.edu.cn).
J. Miši
´
candV.B.Miši
´
c are with the Department of Computer
Science, Ryerson University, Toronto, ON M5B 2K3, Canada (e-mail:
jmisic@ryerson.ca; vmisic@ryerson.ca).
Digital Object Identifier 10.1109/JIOT.2018.2855718
applications. Vehicular fog computing (VFC), in which com-
putation providers are located in close proximity to vehicles,
has been proposed in order to overcome latency and other
constraints [6], [7]. In [6], VFC is defined as a kind of com-
puting vehicles employed as the infrastructure to make the
best utilization of their vehicular communication and comput-
ing resources. In addition, VFC can also provide low latency
and location awareness services for streaming and real time
applications [8]. However, there is not yet a widely accepted
definition for VFC and the associated use cases [9].
This paper considers vehicular fog service (VFS) provided
by a vehicular fog (VF) which is formed on-the-fly by integrat-
ing computing and storage resources of parked vehicles. VF
dynamicity, due to vehicles’ unpredictable arrivals and depar-
tures, leads to various challenges to the reliable and secure
VFS provision to client vehicles. In particular it is impera-
tive to address quality-of-services (QoS) and security issues
occurring in VF [10]. In [11], VFS QoS was discussed from
four aspects: 1) connectivity; 2) reliability; 3) capacity; and
4) delay. In this paper, we focus on connectivity and reliability
of VFS. In terms of security attributes, we focus on confiden-
tiality, integrity, and nonrepudiation of transmitted messages
during the VFS provision.
To achieve continuous, reliable, and secure VFS, we propose
a novel mechanism which includes VF construction method
and VFS access method, based on a novel three-layered system
framework (see Fig. 1). The top layer of the framework is
a central cloud which consists of a fully trusted authority (TA).
In the middle layer, there are VFs, each of which is composed
of a roadside units (RSUs) and some parked vehicles. The
lower layer mainly contains on-board units (OBUs) equipped
on vehicles. In the following discussions, we refer to the vehi-
cles which are the members of VFs as server-vehicles, and to
the vehicles which access VFS as client-vehicles.
In the proposed mechanism, mutual authentication between
RSU and OBU determines whether a vehicle could be a server
in a VF or could access VFS. Authentication is based on the
signature from TA. This paper assumes RSU has deployed
defense mechanisms for detecting abnormal behaviors of vehi-
cles in a VF. Any malicious behavior of vehicles detected
will be reported to TA and then its accessing VF as a server
or client will be revoked. How to monitor vehicle behaviors
and detect abnormality is beyond the scope of this paper.
Container [12] technology is applied to host VFS in order to
assure VFS connectivity and reliability through container liv-
ing migration. It is known that there exist security concerns
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c
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