SECURITY AND COMMUNICATION NETWORKS
Security Comm. Networks
(2015)
Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/sec.1261
SPECIAL ISSUE PAPER
SAFE-CROWD: secure task allocation for collaborative
mobile social network
Xiaochen Fan
1
, Panlong Yang
1
*
, Qingyu Li
1
, Dawei Liu
2
, Chaocan Xiang
3
and Yonggang Zhao
4
1
Institute of Communication Engineering, PLA University of Science and Technology, Nanjing 210007, China
2
Chongqing Communication Institute, Chongqing 400035, China
3
Logistic Engineering University, Chongqing 401331, China
4
PLA Unit 61251, Qinhuangdao 066102, China
ABSTRACT
With the pervasive use of smart mobile devices and increasing wireless networking technologies, collaborations among
mobile users are becoming deeper and ubiquitous. Appropriate task collaborations among mobile users could effectively
improve the network processing ability with so called ‘mobile cloud’ or ‘cloudlet’. However, task allocations confront with
the security issues. The possible collusion or re-collaborations among the mobile users would possibly merge the allocated
tasks of the specific users. Moreover, considering the delivery reliability and task execution efficiency, replications are
applied for enhancement, which would also lead to more sever security threat for users. We investigate how to secure
the security when task collaborations are allowed for mobile users. Our security scheme is built upon the load balancing
scheme, and our intuitive solution is, if the tasks could be effectively balanced among users, the security issues could
be guaranteed, because averaging the task assignment could effectively raise the threshold for collusion among potential
malicious users. In this work, we propose ‘SAFE-CROWD’: a secure task offloading and reassignment scheme among
mobile users. The basic idea is simple, we leverage the ‘ball and bin’ theory for task assignment, where d mobile users in
contact range are investigated, and we select the least loaded ones among them. It has been proved that such simple cases
can effectively reduce the largest queueing length from
log n
log log n
to
log log n
log d
. Inspired by this theoretical result, we
develop a task reassignment policy for security issues. Simulation and trace-driven studies have shown that our simple but
effective scheme could enhance the security for mobile users, when the tasks are collaboratively executed among mobile
devices. Copyright © 2015 John Wiley & Sons, Ltd.
KEYWORDS
security; task allocation; traffic balancing; mobile social network
*Correspondence
Panlong Yang, Institute of Communication Engineering, PLA University of Science and Technology, Nanjing 210007, China.
E-mail: panlongyang@gmail.com
1. INTRODUCTION
Recent years have witnessed a tremendous rise in the per-
vasive usages of smart mobile devices and the associated
applications. With the increasing number of mobile devices
in wireless network, people could effectively share their
data with other mobile users and, further, make deeper
collaborations for each other.
Recently, crowdsourcing with participatory sensing
users calls for deeper collaborations among users. Because
such schemes enable more unconscious users to collabo-
rate in a non-invasive manner and, ultimately, share their
data and tasks for more efficient processing.
In such mobile computing environment, as deeper col-
laborations are needed, the security issues are becoming
the major concerns.
Firstly, for each user, when most of the tasks are
assigned to some specific users, the task features and
the delivering contents are facing tremendous threats,
because small portions of collaborators could jointly
collect more tasks, which could be more challenging espe-
cially for mobile social networks, and identifying the col-
lusion groups is difficult in pure distributed and dynamic
network scenario.
Secondly, the information collection in mobile social
network is difficult. Mobile users would not like to share
their task load information even if it could be used
for enhancing their security issues. Even if all users
would share these informations, the bandwidth require-
ments would be large, because many mobile users’
broadcasting would possibly overwhelm the constrained
bandwidth of distributed wireless network. Even worse,
Copyright © 2015 John Wiley & Sons, Ltd.