Earticle

Yeh et al., in 2002, proposed a one-time password authentication scheme using smart cards. Subsequently, Tsuji et al. and Ku et al. respectively showed that Yeh et al.’s scheme is vulnerable to stolen-verifier attacks. Recently, Lee and Chen proposed an improvement of Yeh et al.’s scheme. Lee and Chen claimed that their improvement can effectively withstand the stolen-verifier attack and is as efficient as Yeh et al.’s scheme. This paper, however, will point out that Lee and Chen’s improvement is still vulnerable to a masquerade attack. And, a simple improvement is given to resist the masquerade attack.

Electronic mail services have become an important source of communication for millions of people all over the world. Due to this tremendous growth, there has been a significant increase in spam traffic. Spam messes up user’s inbox, consumes network resources and spread worms and viruses. In this paper we study the characteristics of spam and the technology used by spammers. In order to counter anti spam technology, spammers change their mode of operation, therefore continues evaluation of the characteristics of spam and spammers technology has become mandatory. These evaluations help us to enhance the existing anti spam technology and thereby help us to combat spam effectively. In order to characterize spam, we collected four hundred thousand spam mails from a corporate mail server for a period of 14 months from January 2006 to February 2007. For analysis we classified spam based on attachment and contents. We observed that spammers use software tools to send spam with attachment. The main features of this software are hiding sender’s identity, randomly selecting text messages, identifying open relay machines, mass mailing capability and defining spamming duration. Spammers do not use spam software to send spam without attachment. From our study we observed that, four years old heavy users email accounts attract more spam than four years old light users mail accounts. Relatively new email accounts which are 14 months old do not receive spam. But in some special cases like DDoS attacks, we found that new email accounts receive spam and 14 months old heavy users email accounts have attracted more spam than 14 months old light users. We believe that this analysis could be useful to develop more efficient anti spam techniques.

The construction of a wireless multimedia ad-hoc network needs to go across the mixed environment with the indoor, the wall-penetration, and the outdoor condition. This paper presents our contribution to address the system design aspects of a multimedia-enabled network based on IEEE 802.11g ad-hoc mode. There are distinct differences between indoor and outdoor environment and penetrating the walls stressed the system limit of the 802.11g ad-hoc mode. Therefore, routing decisions should be made intelligently with the environmental respect to maximize the bandwidth support on the end-to-end paths. By investigating the experimental results of the average throughput with the 802.11g adhoc mode, we have collected the different performance characteristics among the indoor, the wall-penetration and the outdoor environment. Via the experiments and analyses, we have observed that the ad-hoc mode had the worst performance within 5 meters in indoor environments. In outdoor environments, TCP seemed to favor either short distance (e.g., 5 meters) or long distance (e.g., 25 meters). On the other hand, the best performance UDP has achieved with the distance of 10 meters. When the wall-enetration occurs, it is important that the routing nodes in the building edge areas are placed close-by within 5 meters. Given the solid evidences from the baseline experiments, we have embedded the heuristic algorithms into the routing decisions. We have thus simulated a large area of 300 meters by 300 meters with hundreds of routing nodes. After investigating over 100 (randomlygenerated) topology scenarios, the performance results indicate that our proposed scheme produces the higher-bandwidth paths for most of the cases. Even in the less-dense cases, our proposed schemes still can find the better paths with bandwidth about 30% higher than the conventional methods.

Iris recognition is one of important biometric recognition approach in a human identification is becoming very active topic in research and practical application. Iris recognition system consists of localization of the iris region and generation of data set of iris images followed by iris pattern recognition. In this paper, a fast algorithm is proposed for the localization of the inner and outer boundaries of the iris region. Located iris is extracted from an eye image, and, after ormalization and enhancement, it is represented by a data set. Using this data set a Neural Network (NN) is used for the classification of iris patterns. The adaptive learning strategy is applied for training of the NN. The results of simulations illustrate the effectiveness of the neural system in personal identification.

Most of the Soft Computing algorithms will learn from human knowledge and mimic human skills. We survey the principal constituents of soft computing techniques including Fuzzy Logic, Artificial Neural Networks, Support Vector Machines, Probabilistic Reasoning, Genetic Algorithms and Multi-Variate Adaptive Regressive Splines. Soft Computing techniques are being widely used by the IDS community due to their generalization capabilities that help in detecting known and unknown intrusions or the attacks that have no previously described patterns. Due to ncreasing incidents of cyber attacks, building effective intrusion detection systems(IDSs) are essential for protecting information systems security. This paper describes the use of soft computing techniques to detect the unknown intrusions and evidences that soft computing technique is better than previous used techniques to detect the intrusions.

P2P(Peer-to-Peer) is a popular model in distributed computing. We present an access control mechanism based on permission delegation in this paper. This mechanism consists of three protocols, i.e. agency discovering protocol, permission delegating protocol and resource access protocol. Firstly, the task initiator decomposes the task into subtasks and chooses other peers in high trust degree with satisfied abilities to accomplish these subtasks. We call these neighbors as task agents. Then task initiator temporarily transfers some necessary permission to subtask agents by means of credit certificate and delegation certificate. Finally, the subtask agents consume resources of resource peers followed access protocol. These protocols are analyzed in Colored Petri-Net, and simulated with CPN Tools.

Routing in sensor networks is a challenging issue due to inherent constraints such as energy, memory and CPU processing capabilities. The energy efficiency is one of the key concerns in sensor networks for their better performance, as sensor nodes are limited in their battery power. In this research work, different routing algorithms have been studied and the main focus was on geographic routing in sensor networks. A location based protocol EAGR (Energy Aware Greedy Routing) has been presented for sensor networks to extend the lifetime of the network and to get higher data delivery rate and to balance the energy consumption of nodes. In EAGR, each node makes the local decision to choose its next hop. This algorithm works on forwarding rule based on location and energy levels of nodes. Each node knows its own geographic location and its energy levels and the location and energy level of its neighbors. The transmitting node writes the geographic position of destination into the packet header and forwards it to the destination by establishing the sub-destinations. The sub-destination nodes must be alive and geographically near to the destination node to route the packet by choosing the shortest and reliable path. Simulation has been made by using OMNET++. Simulation results show that the proposed algorithm gives better performance in terms of higher data delivery rate and less number of dead nodes. It has been noted that the ratio of successful packet delivery will increase in EAGR as number of nodes increased in the network. Consequently, the proposed algorithm can scale to thousands of nodes in future sensor networks and can effectively increase the lifetime of the sensor networks.

This paper discusses the application of Petrinet as the workflow tool to model urban Traffic system. The paper is divided into phase : the first phase deals with orthogonal extension into phase : the first phase deals with orthogonal extension of Petrinet to enhance the permutation of control and traffic flow simulation. The second phase discusses application of continuous pertinent with intelligent agents to the model the UTS in continuous format with single central control agent.

An optical encrypted color video sequence based on a spectral fusion of information has been proposed. Each color image of the sequence is decomposed into three basic color components. Pertinent information fusion is considered as segmentation. Encrypting consists in modulating each of these three components of the image spectrum by a corresponding phase mask. This phase mask includes pertinent information collected from various encrypted color keys according to a fusion criterion. As encrypting keys are formed by real images, it becomes an impossible task to get the target image by any trial and error random images techniques. For decrypting, a simple algorithm based on segmented correlation filters is proposed. Simulation results corroborate the effectiveness of our algorithm.