This study developed a load balancing early handoff scheme that enables transfer part of heavy load in a base station to the others using the overlap between base stations in wireless cellular networks. The proposed scheme reduces the new call blocking probability (CBP) and handoff call connection dropping probability (CDP) as well as to increase the resource utilization of wireless networks. Since the scheme is triggered by a connection request received by the base station, it immediately reflects the loading of the base station. The proposed load balancing early handoff policy can be integrated in diverse call admission control schemes. The effectiveness of the load balancing early handoff scheme is demonstrated by integrating it with DMTBR to improve the call admission control function. Additionally, NS2 is used to simulate the load balancing early handoff scheme in a wireless network with wrap-around model. The simulation results show that the proposed scheme can effectively improve the wireless network resource utilization.

In many cases side channel attacks complexity are estimated by considering attack simulations only. Regarding this estimations, parameters of cryptographic devices are set so the attack is infeasible. This work shows that this approach to secure cryptographic equipment can be dangerous because real attacks can be much better than expected according to simulations. This observation is presented on very generic Correlation Power Attack using Hamming Distance Power Model. This attack is aimed against integer multiplier implemented in FPGA. In cryptography, an integer multiplier power consumption can sometimes be exploited to reveal a secret. Very often it is in asymmetric cryptography that is used in PKI as a fundamental building block. As an example, there are DSA and its various derivations.

We propose a simple and efficient hash function based on programmable elementary cellular automata. Cryptographic hash functions are important building blocks for many cryptographic protocols such as authentication and integrity verification. They have recently brought an exceptional research interest, especially after the increasing number of attacks against the widely used functions as MD5, SHA-1 and RIPEMD, causing a crucial need to consider new hash functions design and conception strategies. The proposed hash function is built using elementary cellular automata that are very suitable for cryptographic applications, due to their chaotic and complex behavior derived from simple rules interaction. The function is evaluated using several statistical tests, while obtained results demonstrate very admissible cryptographic proprieties such as confusion, diffusion capability and high sensitivity to input changes. Furthermore, the hashing scheme can be easily implemented through software or hardware, and provides very competitive running performances.

In this paper we investigate traffic-engineering issues in Wavelength Division Multiplexing (WDM) all-optical networks. In such networks, the wavelength continuity constraint along with the wavelength clash constraint, lead to poor network performances when dealing with the lightpath provisioning problem. The impact of these constraints is especially severe when traffic demands are unpredictable and characterized by random arrivals and departures. In order to alleviate the impact of these constraints, we propose to employ intentional/active rerouting. Active lightpath rerouting is to intentionally reroute already established lightpaths, during their life period, so as to achieve a better blocking performance. We here assume that due to the large geographic area an optical WDM network can cover, upgrading such a network to support the huge demand for network bandwidth can be costly. Thereby, it is extremely important for network operators to apply traffic-engineering strategies to cost-effectively optimize network throughput. Two new routing and wavelength assignment (RWA) algorithms applying intentional rerouting are proposed. Both algorithms dynamically reroute some already established lightpaths from longer paths to vacant shorter ones so as to reduce the network resources consumption and hence improve the network throughput. The first algorithm, namely, Timer-Based Active Lightpath Rerouting (TB-ALR) initiates the rerouting procedure every time a timer expires. The second algorithm, namely, Sequential Routing with Active Lightpath Rerouting (SeqRwALR) initiates the rerouting procedure when a connection leaves and its lightpaths are released. To the best of our knowledge, our global approach has not already been investigated in the literature. Simulation results show that the proposed active rerouting algorithms yield much lower connection rejection ratios than rerouting algorithms previously presented in the literature while rerouting a small number of already established lightpaths. By rerouting a small number of existing lightpaths, we hope that the disruption period incurred due to rerouting is minimized.

Single Sign-On (SSO) is an authentication mechanism in which a Cloud Service Consumer (CSC) needs to be authenticated only once while accessing vari-ous services from multiple service providers, or when accessing multiple services from the same service provid-er. In the case of Cloud Federation, the consumers can get services from various Cloud Service Providers (CSPs) who are members of the federation, and SSO can be used to verify the legitimate users without requiring them to get authenticated with each service provider separately. CloudSim is a popular tool used for simulating various cloud computing scenarios. As of now, the simulator lacks effective user authentication and authorization methods with it. In this paper, we discuss the design and implementation of SSO mechanism in the Cloud Federa-tion scenario using the CloudSim toolkit. We have used the Fully Hashed Menezes-Qu-Vanstone (FHMQV) pro-tocol for the key exchange and the Symmetric Key En-cryption technique AES-128 for encrypting the identity tokens. We give the workflow model for the proposed approach of SSO in the Cloud Federation and also, the execution time taken in the simulation for various Single Sign-On scenarios where the number of SSO required varies are also shown.

Wireless infrastructure network is vulnerable to Denial of Service (DoS) attack which makes the resources unavailable for its intended user. As an outcome of DoS attack, authenticated user is denied from accessing the network by spoofing legitimate client identity. Reduced protection in management frame led to MAC spoof DoS attack. Though 802.11w was developed to protect the management frame, the network is vulnerable to different DoS attacks and unable to prevent all types of DoS attacks. This motivated us to propose a mechanism to detect and prevent substantial number of DoS attacks. This paper proposes an algorithm called Alternative Numbering Mechanism (ANM) which prevents DoS attacks. The proposed solution is simulated in NS2 for experimentation. Packet delivery ratio, control overhead, normalized routing overhead, delay time, throughput and packet drop were measured for experimentation and to evaluate the performance of ANM. The experimental results of ANM demonstrate that the performance of ANM is encouraging and prevents nearly all types of DoS attacks.

Investigations in hydrologic sciences are bounded because most of existing water surveillance methods are manual. Such systems are incapable to gather information at spatial and temporal level due to location constraints. In this paper, we present a new communication architecture for Underwater Wireless Sensor Network (UWSN) based on acoustic communication. However, unique challenges offered by underwater environment are main hindrance in deployment of UWSN in real life applications. So, we discuss various communication methodologies to figure out which one suits best to the requirements of UWSN. Our simulation results illustrate change in data transmission rate, energy consumption and transmission time w.r.t transmission range and number of nodes in network. Results prove that multi-hop communication offer high transmission rate, large bandwidth. Moreover, multi-hop communication is much more energy and time efficient than direct communication.