JOURNAL OF ELECTRONIC AND CYBER DEFENCE
Year:2014 | Volume:2 | Issue:3 (7)|Papers Count:7

This paper concerns locational finding in broadband wireless networks in corporating OFDMA technique at the plysical layer. In this regard, a novel estimation method is proposed to find the position of active users. This method makes use of the power spectral density of the received signal from a specific user to compare its likelihood to that of some reference points. Despite the conventional method which performs well in a single path environment, the proposed method not only robusts in a muli-path environment, but also it inherently incorporates path delay spreads to find the location of exiting users. Simulation results indicate that the mean estimation error in the wimax network operation is around 11 meters at 3.5 Ghz with 5 Mhz bandwidth and when reference points are 26.4 meters apart relying on SUI model.

Anonymous networks provide data confidentiality and anonymity as two important factors through the Internet. In recent years, with growing of quantum computing and also newly performed attacks, it's necessary to reform classic anonymous networks like Tor. So we need a new architecture which is quantum- resistant. In the other side, this is important to block attacks like user identity detection so we need to revise classic structures. In this paper, we propose a lattice-based architecture which includes NTRU cryptographic system and NSS digital signature. Finally, the structure of the anonymous networks has been revised according to the performance requirements and security issues. The proposed architecture should be quantum-resistant that is investigated within highly practical security analysis.

Today, virtual machines play an important role in efficient and effective management of resources. Virtualization is the concept of creating multiple virtual machine guests on a single hardware that allows the system to provide optimal use of resources. Common behavior of malwares in a virtual machines is wide. Sometimes these malwares change the system objects in the first step, and next, influence the host operating system of the virtual machine at the time of completion of the work, and maybe in a final step they do some malicious task. In this paper we provide a secure method for identification, classification and elimination of malwares in a virtual machine. The proposed method which is called, SSM, will firstly attempt to identify high-risk behaviors using behavioral profiles and evaluating changes. The proposed method is then extracted from pre-treatment to categorize malicious groups. Experimental results show that the sample rate of false negatives has sharply declined. The proposed mechanism is based on the actual samples virtualization Xen, with the Linux implementation. Through detailed analysis, and comparison SSM with current commercial anti-malware, SSM has a good performance in the detection and removal of malware, as well as reducing the rate of false- negative samples were found in a virtual machine.

Covert timing channels are used in transmitting information in a secret way. Jitter and packet loss are two important noises that affect Covert Timing Channel performance. Several studies on evaluating capacities and robustness of covert channels were done, but all those were based on measurement in real environment or computational methods. Measurement in real environment and computational methods do not have the capacity of creating special circumstances and evaluating the channel in those circumstances. In the present research, a covert timing channel on the Internet consisting two packet losses and jitter noises was simulated using Petri-Net. Also, capacity and robustness criteria of channel were evaluated. The results of the simulation showed that weibull distribution function to modeling HTTP traffic transmitter, laplacian distribution function to modeling network jitter and bemoulli distribution function to modeling packet loss are careful enough. Also, parameters of these models obtained to optimum capacity and robustness.

Automatic text summarization systems are one type of management systems of huge information. This paper discusses one type of Persian text summarization based on a query named "an extractive text summarization" which is very useful for leaders to review information about special topics. The most important phase in this type of summarization is calculation of the similarity between the query phrase and components of the original text. For this purpose, after preprocessing the phase, converting the query to a sentence, and clarifying the word sense, it is possible to calculate the similarity between the query phrase and sentences using Farsnet. Then, those sentences that are the most similar to those in the query are selected to be used in the summary. The results of the proposed method show that this method results in quite acceptable success. Since Persian is very young in processing the original language, this paper and all alike can be a great help to its result improvement.

In this article we propose a file analyzer based on sandbox in the client side. This analyzer environment is used for safe execution of a suspicious application to find its behavior and determine if it is safe or not. This sandbox can also be used for behavioral modeling of a malware by in hand execution for understanding distractive and infecting pattern of malwares for creating disinfection and a cleaner method. The advantages of proposed method is in reducing problems with malware detection specifically in detection of obfuscated and metamorphic malwares that can't be detected by signature and static base analysis methods. So this contains the main goal of this article for providing platform of dynamic analysis. Proposed sandbox can monitor and track incoming requests of an application in both user and kernel mode of operating system. This article clusters incoming requests in 8 families with performing data mining on 21000 samples of malwares and benign files and replying them with 5 policies y including logging, redirection, rejecting, cheating and emulating of system resources. Our sandbox guarantees health of operation system during execution and analysis of malwares. In addition this article discusses challenges on dynamic analysis and analyzer environment and gives solutions for them. Most of the challenges focus on methods of detecting and bypassing analyzer environments. At last, this article evaluates the proposed sandbox based on the potentiality and capabilities of behavioral tracking and usage of system resources and compares it with some top famous analyzers in the word.

Due to the epidemic growing of telecommunication systems and new services, the demand for radio frequency spectrum has greatly increased to the extent that the radio frequency spectrum has been a vital source of value to radio communications. Therefore, managing the efficient use of the frequency spectrum of the different technologies and different services is very difficult. In the past, this was done by assigning afrequency spectrum for each service, But another way to solve this problem is based on the characteristics of a modulation that shares the frequency band without significant interference. This method is called spread spectrum modulation. Spread spectrum steganography method uses a spread spectrum communication concept in which a narrow- band signal is transferred into a pseudo-noise signal. This method shows a very high ability to withstand adverse interactions. It also has security advantages of the encryption based on the keys used in the production of different strings pseudo-random orthogonal - such as Gold strings. To spread the message signal spectrum, the Hadamard matrix is used with appropriate statistical properties of low cross-correlation. In this paper we have studied Steganography by Hadamard matrix and it is compared with a simple method.