A vehicular ad hoc network (VANET) is the emerging technology that allows the drivers to keep the road safety throughout the journey. In VANETs, vehicles can collaborate with each other by exchanging the messages. When these messages are incorrect, drivers will have to face many serious problems which include traffic congestion and minor to fatal road accidents. Therefore, drivers need a method which provides the correct decision using risk analysis calculated from the vehicle context. For this purpose, we propose a new contextual risk-based decision methodology for vehicular networks. This methodology can be used to provide robust and reliable decisions.

Privacy protection is of extreme importance especially in security sensitive environments. Neither cryptography nor steganography comes up with ultimate solution for privacy preservation in open systems. However, combination of steganography and cryptography can greatly increase the security of communication and is usually considered a good practice for securing security driven communication environments. In this paper we propose a novel scheme for image authentication and secret data sharing based on three level security model viz: Compression, steganography and cryptography. Compression optimizes the resource usage, steganography conceals the existence of message and cryptography is used to achieve confidentiality and authentication.

Honeypots are effective network security systems built to study the tactics of attackers and their intents. In this paper, we deployed Kippo honeypot to analyze Secure Shell attacks. Both the dictionary attack and intrusion activities of attackers have been discussed. We collected usernames and passwords that are attempted by dictionary attack targeting Secure Shell service. We have traced the frequently attacking machines based on their IP addresses. We have also recorded the commands they executed after successful logins to the Secure Shell honeypot server. We logged vast amount of connection requests destined to number of ports originated from different locations of the world. From our honeypot system, we have collected attack data that enables us to learn common Secure Shell based attacks.

In 1990, Guillou and Quisquater published an article where they described a new digital signature system. Their technique was based on the RSA algorithm. In this paper, we present several modified Guillou-Quisquater digital signature protocols. We discuss their security and complexity. These schemes can be seen as alternative signature methods if existing systems are completely broken.

Due to the enormous growth of network based services and the need for secure communications over the network there is an increasing emphasis on improving intrusion detection systems so as to detect the growing network attacks. A lot of data mining techniques have been proposed to detect intrusions in the network. In this paper study of two different classification algorithms has been carried out: Na?ve Bayes and J48. Results obtained after applying these algorithms on 10% of the KDD’99 dataset and on 10% of the filtered KDD’99 dataset are compared and analyzed based on several performance metrics. Comparison between these two algorithms is also done on the basis of the percentage of correctly classified instances of different attack categories present in both the datasets as well as the time they take to build their classification models.Overall J48 is a better classifier compared to Na?ve Bayes on both the datasets but it is slow in building the classification model.

Congestion control approaches, source based approach and router based approach have their own limitations. In source based approach, it is difficult to get correct location of congestion and without proper admission control; we cannot effectively manage the congestion problem. Thus both the approaches have to work in coordination for effective congestion control. In this context, an interaction study plays an important role to verify how a TCP implemented at source end works with Active Queue Management at router end. In this paper, we analyzed the performance of different high speed TCP variants at the source end with some recent AQM approaches: CoDel and sfqCoDel. The main objective of this work is to obtain the interaction patterns of different high speed TCP variants like: HTCP, Compound, HSTCP, Scalable and Cubic with recently proposed AQMs: CoDel and sfqCoDel. Simulation results show that that if we want to achieve a better throughput, minimum delay and improved fairness simultaneously, Cubic-sfqCoDel may be a good choice of TCP-AQM combinations for high speed networks.

Group communication over multicast ad hoc network suffers from insufficient utilization of limited resources, i.e. shared channel, battery, data processing capabilities and storage space etc. Multicast routing protocol should be able to manage all these resources because their consumption depends upon different factors, i.e. Unicast/Multicast network operations, dynamic topology due to mobility, control overhead due to scalability, packet loss and retransmission due to collision and congestion etc. All these factors may cause unnecessary network load, delay and unfair resource utilization. However, multicast ad hoc routing protocols are more efficient than Unicast routing protocols, but they also suffer from performance degradation factors discussed above. Researchers have developed various layer wise solutions for resource optimization. In this paper, we will explore the different schemes for fair utilization of network resources.

Peer-to-peer networks are widely used today. Due to this wide use, they are the target of many attackers. The most mentionable of them is the Sybil attack. This is an attack in which it creates many fake identities. In this paper, the detection scheme and efficient mitigation mechanism to counteract Sybil attack in the peer-to-peer network is proposed. The proposed Sybil detection scheme is used to detect Sybil attack. The detection of Sybil attack is depending upon the behavior of the packets. The identity and the location of the packet are checked. If the location and identity of the packet are changed than that of the mentioned, the packet is detected as a Sybil attack. Sybil mitigation scheme is the combination of cost incurred method and certified authentication method. The Sybil packet will be removed by closing read/write operations. The proposed scheme is evaluated on the basis of detection rate and false positive rate. The experimental results show that Sybil attack is accurately detected by the proposed system in terms of low false positive rate and high detection rate. Moreover, the proposed system works efficiently in terms of Sybil detection rate and false positive rate.