SAFE-CROWD: Secure task allocation for collaborative mobile social network

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 θ(log n/log log n) to θ(log log n/log d). Inspired by this theoretical result, we develop a task reassignment policy for security issues. Simulation 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.