Huddle hierarchy based group key management protocol using gray code

Secure and reliable group communication is an active area of research. Its popularity is fuelled by the growing importance of group-oriented and collaborative applications. The central research challenge is secure and efficient group key management. The present paper is based on the huddle hierarchy based secure multicast group key management scheme using the most popular absolute encoder output type code named gray code. The focus is of twofolds. The first fold deals with the reduction of computation complexity which is achieved in this protocol by performing fewer multiplication operations during the key updating process. To optimize the number of multiplication operations, the fast Fourier transform, divide and conquer approach for multiplication of polynomial representation of integers, is used in this proposed work. The second fold aims at reducing the amount of information stored in the Group Center and group members while performing the update operation in the key content. Comparative analysis to illustrate the performance of various key distribution protocols is shown in this paper and it has been observed that this proposed algorithm reduces the computation and storage complexity significantly.     

A Distributed Mechanism for Handling of Adaptive/Intelligent Selfish Misbehaviour at MAC Layer in Mobile Ad Hoc Networks

Medium access control(MAC) protocols such as IEEE 802.11 are used in wireless networks for sharing of the wireless medium.The random nature of the protocol operation together with the inherent difficulty of monitoring in the open poses significant challenges.All nodes are expected to comply with the protocol rules.But,some nodes in order to gain greater benefits misbehave by not complying with the rules.One such selfish misbehavior is waiting for smaller back-off intervals when compared to the other node...     

An efficient list-based task scheduling algorithm for heterogeneous distributed computing environment

The task scheduling in heterogeneous distributed computing systems plays a crucial role in reducing the makespan and maximizing resource utilization. The diverse nature of the devices in heterogeneous distributed computing systems intensifies the complexity of scheduling the tasks. To overcome this problem, a new list-based static task scheduling algorithm namely Deadline-Aware-Longest-Path-of-all-Predecessors (DA-LPP) is being proposed in this article. In the prioritization phase of the DA-LPP algorithm, the path length of the current task from all its predecessors at each level is computed and among them, the longest path length value is assigned as the rank of the task. This strategy emphasizes the tasks in the critical path. This well-optimized prioritization phase leads to an observable minimization in the makespan of the applications. In the processor selection phase, the DA-LPP algorithm implements the improved insertion-based policy which effectively utilizes the unoccupied leftover free time slots of the processors which improve resource utilization, further least computation cost allocation approach is followed to minimize the overall computation cost of the processors and parental prioritization policy is incorporated to further reduce the scheduling length. To demonstrate the robustness of the proposed algorithm, a synthetic graph generator is used in this experiment to generate a huge variety of graphs. Apart from the synthetic graphs, real-world application graphs like Montage, LIGO, Cybershake, and Epigenomic are also considered to grade the performance of the DA-LPP algorithm. Experimental results of the DA-LPP algorithm show improvement in performance in terms of scheduling length ratio, makespan reduction rate , and resource reduction rate when compared with other algorithms like DQWS, DUCO, DCO and EPRD. The results reveal that for 1000 task set with deadline equals to two times of the critical path, the scheduling length ratio of the DA-LPP algorithm is better than DQWS by 35%, DUCO by 23%, DCO by 26 %, and EPRD by 17%.     

Collaborative Polling based Routing Security Scheme to Mitigate the Colluding Misbehaving Nodes in Mobile Ad Hoc Networks

The recent advancements in the field of wireless communications makes the mobile devices to communicate with each other in a self organized manner without relying on stable infrastructure. It requires cooperation between the mobile devices in order to find routes between them when the nodes are not in the communication range of each other. The misbehaving node comes into existence due to scarcely available resources such as battery, bandwidth and computational power. When the nodes collude to misbehave then it further makes the routing process difficult due to frequent network partitioning and it also degrades the overall network throughput. This paper proposes a Collaborative Polling based Routing Security Scheme to detect and isolate the colluding misbehaving nodes in mobile ad hoc networks. The proposed system employs a timeout approach to detect the active neighbors in the neighborhood before monitoring the transmissions which involves it. It ensures that the false detection of a good node as a bad one has been greatly reduced which in turn decreases the send buffer drop because of the availability of alternate routes. The simulation result shows that the measured parameters such as packet drop ratio and malicious drop has been reduced due to the efficient detection and isolation of misbehaving nodes. This paper also presents an analytical and simulation results of the impact of node misbehavior.