نشریه منادی امنیت فضای تولید و تبادل اطلاعات (افتا)
سال پنجم شماره 1 (پیاپی 9، بهار و تابستان 1395)

Recently, software defined networks have been introduced for innovation and flexibility in computer networks. They are widely used in infrastructure networks and data centers. Using these networks has advantages such as scalability, efficient bandwidth usage, reducing control traffic, better traffic engineering and etc., which are mainly due to their programmability. There are also some security challenges that often arise from the same property. Software defined networks reliability compared to traditional network reduces due to these challenges. Therefore, if software defined networks are not design based on a security architecture, they will be vulnerable against known cyber-attacks such as DDoS, spoofing, information disclosure and etc. In this paper, software defined network security challenges and corresponding solutions are reviewed. Moreover, some applications of software defined networks for security including network traffic separation, network flow access control, and secure routing are mentioned. In order to do security testing and evaluation of relevant security solutions we have explained how these networks are simulated.

The stream ciphers are set of symmetric cipher algorithms that receive the secret message as a sequence of bits and process encrypted operation using complex function according to key, IV and XOR combination of a sequence of bits. One of the goals in the design of stream ciphers is to get minimum great period using one of the primary T-functions. Also using jump index in designing LFSRs lead to complexity of stream ciphers based on LFSR analysis. In this paper, tried with using of T-functions concepts and jump index, a novel method presented for primary functions design with great period.

Cloud computing is a model based on computer networks and also it is a new pattern for supply, consumption and computer services delivery. Security is a large challenge in the cloud for extensive scale. So, in the decision for using the suitable cloud services provider, provider validity is very important. In the current research, many types of characteristics and methods for investigating the valid and invalid providers are studied in order to suggest general and extensive survey in cloud services provider validity. Research results showed that in spite of presenting a set of characteristics for cloud services providers, most of the comparison cases are intuition form and there is not a special scientific method for comparison and suggesting valid providers according to user requirements. By evaluating the studied characteristics, 10 important characteristics in general and special form were presented for cloud services provider validity measuring. Since classifying and clustering are based on characteristics investigation, so we can solve valid and invalid cloud provider’s recognition issue as a classifying problem. There are different problem solving for mentioned cases, which neural network is regarded one of them.

In mathematics and computer science an optimization problem, the problem is finding the best solution among all possible solutions. Given the importance of the knapsack in computer sciences, different algorithms are used to solve it. Knapsack problem is a combinational problem of selectivity and the purpose of solving the most benefit by taking the capacity is the tolerable knapsack. Since the knapsack is a problem of constrained maximization. In this study, a mathematical model in the form of a function unlimited minimization and designed for it, hen this model on Particle Swarm Optimization , Firefly Algorithm and Artificial Bee Colony has been implemented in MATLAB software environment, The results show that the artificial bee colony algorithm, the model is better than the other two algorithms .The advantage of this model is the objective function , because minimization and unlimited models , to implement with many Bio-Inspired algorithms.

Cloud environment are known as a revolution in IT industry in the recent decade and many organizations have used this service for data processing and data storage. Despite of fast growing and numerous advantages, some organizations still do not use this service due to security problems and privacy issues related to storing sensitive data on the untrusted cloud servers. Access control management utilizing encryption techniques is one of the most common methods to solve these kinds of problems. Attribute based encryption is a new cryptographic model which uses descriptive attributes and access structures for managing access control. This article discusses the most recent methods of access control in cloud environment using attribute based encryption. We classify these protocols with respect of efficiently and security features. Finally, all the strengths and weaknesses points of reviewed articles are discussed and a comprehensive security and practical comparison is presented.

Wireless Sensor Networks (WSNs) are an ideal solution for miscellaneous applications of surveillance and control, such as traffic control, environmental monitoring, and battlefield surveillance. The wireless sensor nodes have limited memory and processing capability. The Sybil Attack is a serious threat in which a malicious node creates multiple fake identities in order to mislead the other sensor nodes. This attack can have influence on routing protocols and the operations like voting and data aggregation. In this paper, we present a dynamic and lightweight algorithm with a confidence-aware trust approach. The Algorithm uses the trust value of each sensor node to reduce the false alarm rates and detect indirect Sybil attacks in WSNs. The simulation results demonstrate that the average detection and wrong detection rates are 92% and 0.08% respectively.