فصلنامه پدافند الکترونیکی و سایبری
سال چهارم شماره 3 (پیاپی 15، پاییز 1395)

Wireless Sensor Networks (WSNs) are the type of Ad Hoc networks that can be used in critical and dangerous environments to collect, process and exchange their data. WSNs consist of a large number of low-cost sensor nodes that are small and have limited resources like power, memory and processing power, that have been deployed as dense and random. Due to the nature of WSNs are faced with multiple threats and vulnerabilities such as physical attacks, the recovery key attacks, reducing power attack, and etc. Therefore, any authentication scheme for these networks should be resistant against these attacks. In this article, we examine the strengths and weaknesses of the proper WSNs authentication schemes and a new authentication scheme based on block cipher lightweight PRESENT for the security of these networks is suggested. The proposed authentication scheme covering the previous weaknesses compared with other schemes of less computational complexity, increased security and better efficiency.

Phishing is one of the social engineering techniques to deceive users to obtain confidential information such as user names, passwords or bank account information is used. The most important challenges in the Internet, is the risk of phishing attacks and internet fraudulent. So researchers have been attempted to identify and deal with such attacks. The aim of this study is to present a new method for identifying phishing website in Internet banking. The proposed method have not weaknesses of identifying and deal with phishing methods such as the lack of checking the status of free of charge website hosting and lack of focus on internet banking. This method uses the advantages of the different techniques to identify phishing website and identify possible moment zero Persian-language phishing websites that attack to Iran's Internet banking services. The proposed method is assessed by using a set of legal websites includes 500 pages indexed in links site and phishing websites set contains 100 phishing site detected in PhishTank and 20 phishing site designed and 11 phishing site identified in during writing the article. The results indicated that the proposed approach, does not consider phishing websites as legitimate (positive error of zero percent) and only 3% of phishing websites does not recognize (3% negative error).

Parameter Estimation is an essential step in data detection. In this paper, we design a method to estimate the essential parameters for direct sequence code division multiple access (DS/CDMA). The focused original parameters are Direction of Arrival (DOA). This parameter has significant role in data detection as well as enhancing the quality of receivers. Since the DS/CDMA Signal transmitter applies redundancy code technique in order to send data, the parameter estimation is designed to take the greatest advantage of this redundancy. DOA’s estimation is handled using array processing methods. Signal correlation issue is tackled with developing an orthogonal projection passing through multi paths channel. Besides, combining the subspace and Eigen decomposition methods succeed to substantially increase the efficiency of DOA’s estimator. In our proposed method it is not required to search all angles as in conventional methods. Another advantage of this algorithm is that number of users can exceed the number of antenna arrays contrary to many of the conventional methods. At the end, some simulation results are illustrated to confirm the efficiency of the method.

Today, modeling and generating normal network traffic is a very important. In existing works, the features of network traffic are modeled using probabilistic distributions. In this paper, a new method is proposed for modeling the features of network traffic. The proposed method is based on the Zipf’s law. The Zipf's law is an empirical law that provides the relationship between the frequency and rank of each category in data set. In this paper, we will show that the Zipf’s law can model different features of network traffic in a good manner. For this propose, two important features of network traffic, i.e., length and inter-arrival time of TCP and UDP packets, are examined. The proposed method for modeling the features of network traffic can use in various applications areas, such as, simulation or generation of the normal network traffic. The advantage of this law is that it can provide high similarity using less information. Furthermore, the Zipf’s law can model different features of network traffic that may not follow from probalistic distributions. The simple approach of this law can provide accuracy and lower limits from existing methods. Furthermore, the proposed method can provide good times for modeling and simulation.
In this paper, we will show that by classifying the feature values and obtaining their ranks, we can create an accurate modeling of features. In other words, the rank of each category will be the model resulting from the feature values that can be used in simulation.

Most malware producers use obfuscation techniques to bypass signature-based detections. In order to provide proactive and real-time protection, the researchers have begun to develop strategies for behavior-based detection. While behavior-based detection techniques are promising solutions to this growing problem of malwares varieties, but they still suffer from high false positive rate in detecting unknown malware detection. To overcome this problem, we shall seek for identifying patterns, representing malicious intent in all instances of a malware family. In this paper, we propose a new technique, based on discriminative subgraph mining technique to identify discriminative behavioral patterns. The malicious behavioral patterns discovered by our technique from a known malware set allows the detector to reach an 94% detection rate over unknown malware with no false positives. This is a significant improvement over the 55% detection rate observed from commercial antivirus, and the 86% rate reported by the best behavior-based detector.

This paper proposed a method to create deception jamming against a SAR with diving platform. It is assumed jammer is stationary on the ground. SAR imaging, using two dimensional modulation frequency and creating false target in the desired coordinate, using the Range Doppler Algorithm and Based on the inherent relationship between time delay and frequency shift characteristics will be described. Finally this paper deducts general output form of shift frequency jamming in a SAR with diving platform. according to the simulation and using fitted expressed relationship can be conclude, if the jammer applied frequency shift radar signal, false target will distance from real target in Azimuth, and time delay causes a false target that is far away from real target in Rang dimension. From the results of this paper can be used in order to passive defense against radar threats, especially creating false target in SAR, of opposing force.

When a user moves among a set of access points in a wireless network, the handoff operation occurs as a result of his getting constantly connected to multiple access points to get a desired service; however, frequent handoffs may disrupt his association in the network. This study aims to minimize the number of handoffs for a set of users. This problem is analyzed by considering two cases for the user’s movement: (i) each user can have his chosen path within the network, and (ii) all users move together and they have group mobility. In the first case, having the connectivity assumption; that is when a user “u” connects to an access point “a”, while “a” is available, “u” remains connected to “a”, this thesis proves that there is no competitive algorithm in an online setting for handoff minimization under connectivity assumption. However, in the second case, it proposes an optimal competitive ratio algorithm for the problem.

In this paper we propose a (3,3)-threshold semiquantum secret sharing protocol without entanglement in which the quantum service provider shares a secret key with three classical parties who are restricted to measuring the qubits in the classical basis {0, 1} and sending or reflecting the qubits without disturbance. Also entanglement is not necessary in this semiquantum secret sharing protocol especially when the number of the parties of secret sharing is large. The presented protocols are also showed to be secure against eavesdropping.