Underwater sensor network has been burgeoned as an interesting research area which has to face a couple of challenges to provide scalable and efficient routing services because of its unique characteristics. In many aspects, it differs from the ground based terrestrial sensor network, Firstly, In UWSNs, acoustic signal is used instead of radio-frequency that attenuates much in underwater environment in comparison with radio-frequency channels. Acoustic channels attribute much lower bandwidth and the propagation speed of acoustic signals in water is several of magnitudes longer. Secondly, nodes of underwater sensor networks move with water current which results dynamic topology. Thirdly, underwater sensor networks consume more power than terrestrial networks due to the underwater channel characteristics and it has high error probability because of acoustic underwater channels' sensibility in noise, multi-path and Doppler spread. Some routing protocols have been proposed to deal with these challenges. But most of these protocols espouse the greedy technique to forward packets to the neighboring node which consumes a lot of energy when network is dense. In this thesis, we propose a Priority Metric Based Ad hoc Routing Protocol for UWSNs. The leading advantages of the protocol are that it consumes less energy in dense network as only one neighboring node needs to capture the packet and process it and it guarantees less number of packet loss in high mobile node environment. Extensive simulation is executed to attest the competence of the proposed routing protocol. The result and analysis bear the indication of the proposed routing protocol's surpassing the existing routing protocol in terms of total energy consumption and average end to end delay.

In this paper, a novel load balancing technique is proposed to handle biased call request patterns efficiently. The knowledge of call request patterns is used from trace-based analysis; call patterns are affected by various factors such as geographical context, user mobility, network usage patterns and temporal bias. A call routing system is modelled as a network of queues and a provisioning algorithm is developed. The proposed model employs a combination of predictive and reactive provisioning methods. The idea of Capacity Distribution is introduced- a heuristic for heterogeneous capacity allocation among adjacent cell pairs. The proposed model retains simplicity while being able to effectively learn from the variations in call patterns. The performance of the model is evaluated using extensive simulation techniques.

To guarantee the performance of ad hoc networks, utilizing a hierarchical architecture model is necessary. An instance of this structure is clustering. In this paper a cluster-based topology control algorithm is proposed which builds an energy-efficient and a low interference topology. It uses low-quality information, exchanges a few messages, and does not need for extra hardware equipment as well. It is also suitable for practical use, because in the implementation of this algorithm is not needed to know the location or the direction information of the network nodes. So it is possible to classify this algorithm as a neighbor-based topology control algorithm. In addition, for the transmitting and the maintained power levels of each node, a modification is applied according to the real hardware platforms. It improves the energy consumption in the ideal conditions.

Security issues have been emphasized in MANET due to its vulnerability to unauthorised access and unshielded broadcasting nature of communication. In this paper we present a trust based AODV for MANET. The trust takes into account the eligible neighbours based on reliability, residual energy, and speed. Thus our algorithm provides a reliable, energy efficient routing technique. The multi-criteria trust values are calculated using fuzzy-logic. This algorithm is capable of putting aside the selfish nodes. As only trusted neighbours are selected for packet delivery, energy consumption also diminishes because the transmitting node does not need to deliver packets to the untrusted neighbours. Less number of transmissions renders low energy consumption. Absence of selfish nodes in the selected neighbours at every hop provides better packet delivery and hence better throughput.

Mobile Adhoc NETwork (MANET) consists of mobile nodes that can move freely and route packets without aid of centralized infrastructure. Dynamic changing topology, limited battery power and lack of centralized trusted authority make it vulnerable to several attacks and lot of research is being carried out in the field of security by discovering attacks, evaluating the damage caused to the network and developing solutions to combat such attacks. This paper simulates one of the most malicious behaviors known as blackhole attack. The blackhole node creates forged reply, advertising valid and fresh route to destination and thereafter drops data packets maliciously. The analysis guides us to the various performance parameters such as throughput, packet delivery fraction, normalized routing load and number of dropped packets evaluated over different scenarios.

"Maintain the security of the secret information", this words has been a great challenge in our day to day life. Sender can send messages regularly through a communication channel like Internet, draws the attention of third parties, hackers and crackers, perhaps causing attempts to break and expose the unusual messages. Steganography is a gifted region which is used for secured data transmission over any public media. Wide quantity of research work has been established by different researchers on steganography. Steganalysis is an art and science of detecting messages hidden using steganography. Some research work has also been remarked in the field of Steganalysis also. In this contribution, we have gone through steganalysis attack of some established text steganography tools.

An efficient Query-Reply based routing protocol for mobile networks is proposed in this paper. The alternative paths have been generated between source and destination nodes in the network. A Directed Acyclic Graph (DAG) is developed on the basis of selected right path among the alternatives. The reachability relationship is established on DAG and subsequently it introduces a proactive routing approach. As a result, the time complexity for the proposed routing method is reduced to a desired extent. The simulation studies confirm the improvements of the proposed model over the others.

Network firewalls act as the first line of defense against unwanted and malicious traffic and also represent critical point of failure during DDoS attack. Predicting the overall firewall performance is crucial to network security administrators and designers in assessing the strength and effectiveness of network firewalls against DDoS attacks. In this paper, authors have made a humble attempt to study and compare DDoS performance of various types of firewalls in operation as on today. Analysis and detailed comparison is performed on open source packet filter (PF) firewall, Checkpoint SPLAT and Cisco ASA in a testing environment with laboratory generated DDoS traffic. It is attempted to identify various firewall DDoS performance parameters which can be considered during DDoS attack. Further, experiments are carried out to study effect of varying TCP Opening Timers on performance of stateful inspection firewall during Sync Flood attack. Also, in order to improve performance, intelligence is applied in PF firewall rulebase to mitigate DDoS.

A Mobile Ad hoc NETwork (MANET) is a wireless communication network with minimum physical infrastructure with diverse communication applications. Mobility and Multihopping are the main characteristics of MANET. Multipath routing protocols establish multiple routes between nodes. The construction of multiple routes should be done with minimum overhead and bandwidth consumption. The purpose of this article is to analyze the characteristics and functionality of various multipath routing protocols and to do the performance comparison between these multipath routing protocols to choose the best among them to use in large networks.

The biometric passports are to prevent the illegal entry of traveler into a specific country and limit the use of counterfeit documents by more accurate identification of an individual. This IC chip is integrated into the cover of a passport, called a biometric passport. Biometric Passports have been introduced in many countries to improve the security in Inspection Systems and enhance procedures and systems that prevent identity and passport fraud. The electronic passport is the privacy and security risks that arise by embedding with biometric technology. The goal of the adoption of the biometric passport is not only to expedite processing at border crossings, but also to increase security. Policymakers have put their faith in the technological promise of biometric identification because absolute identification could eliminate mismatched computer records and stolen identities.