There is a new approach to determine the degree of cryptographic S-boxes suitability. This approach is based on estimating the number of transformation cycles required for a cipher to achieve differential and linear nature of the state typical for random substitution of the appropriate degree. The paper presents the results of experiments to determine the differential and linear indicators of the Heys cipher (a cipher with a weak linear transformation) and a reduced model of the Rijndael cipher (the cipher with a strong linear transformation), using nibble S-boxes with different values of the XOR table differences maxima and linear approximations table displacements. It is demonstrated that, contrary to widely-known approach that links cipher performance indicators with strength indicators of substitutions that they use, the resistance to cipher attacks by means of linear and differential cryptanalysis (maximum differential and linear probabilities) does not depend on S-boxes used. It is concluded that random substitutions can be used as the S-block designs without compromising the performance of cryptographic ciphers. It means that the search for S-boxes with high encryption performance (at least for ciphers with strong linear transformations) is an unpromising task. At the same time it is shown that a good cipher can not be built without a nonlinear transformation. S-boxes (non-trivial type) are essential and necessary elements of an effective cryptographic transformation, ensuring the operation of the nonlinear mixing of input data blocks bit segments.

Peer-to-Peer (P2P) systems are widely used for data sharing applications in an autonomous and decentralized mode. P2P systems are suitable for large-scale distributed environments in which nodes can share resources other than data such as computing power, memory and network bandwidth. Some of important parameters that affect the performance of P2P systems are peer availability, data availability, network overhead, overlay structure, churn rate, and data access time.
In this paper a self organized replica overlay scheme "Improved Hierarchical Quorum Consensus" (IHQC) for P2P systems is proposed. This scheme organizes replicas in a Self Organized Hierarchical Logical Structure (SOHLS) that has special properties. The scheme improves performance of the system by reducing search time to form read/write quorums, reducing probability of accessing stale data, improving degree of intersection among consecutive quorums and reducing network overhead. This scheme is highly fault tolerant (tolerate up to faults) due to replication of data and inherits the best property of Read-One-Write-All (ROWA) protocol in a dynamic environment of P2P network. The architecture for IHQC is also proposed for implementing the scheme that supports improved performance of P2P systems. This scheme also maximizes the degree of intersection set of read and write quorums; hence, having higher probability to get updated data as compared to all other schemes. The mathematical correctness of the scheme is also presented in the paper. The results of simulation study of the proposed scheme also support and verify its better performance than Random and Hierarchical Quorum Scheme.

This paper is a contribution in the field of security analysis on mobile ad-hoc networks, and security requirements of applications. Limitations of the mobile nodes have been studied in order to design a secure routing protocol that thwarts different kinds of attacks. Our approach is based on the Zone Routing Protocol (ZRP); the most popular hybrid routing protocol. The importance of the proposed solution lies in the fact that it ensures security as needed by providing a comprehensive architecture of Secure Zone Routing Protocol (SZRP) based on efficient key management, secure neighbor discovery, secure routing packets, detection of malicious nodes, and preventing these nodes from destroying the network. In order to fulfill these objectives, both efficient key management and secure neighbor mechanisms have been designed to be performed prior to the functioning of the protocol.
To validate the proposed solution, we use the network simulator NS-2 to test the performance of secure protocol and compare it with the conventional zone routing protocol over different number of factors that affect the network. Our results evidently show that our secure version paragons the conventional protocol in the packet delivery ratio while it has a tolerable increase in the routing overhead and average delay. Also, security analysis proves in details that the proposed protocol is robust enough to thwart all classes of ad-hoc attacks.

The search for the periodicity in time-series database has a number of application, is an interesting data mining problem. In real world dataset are mostly noisy and rarely a perfect periodicity, this problem is not trivial. Periodicity is very common practice in time series mining algorithms, since it is more likely trying to discover periodicity signal with no time limit. We propose an algorithm uses FP-tree for finding symbol, partial and full periodicity in time series. We designed the algorithm complexity as O (kN), where N is the length of input sequence and k is length of periodic pattern. We have shown our algorithm is fixed parameter tractable with respect to fixed symbol set size and fixed length of input sequences. Experiment results on both synthetic and real data from different domains have shown our algorithms' time efficient and noise-resilient feature. A comparison with some current algorithms demonstrates the applicability and effectiveness of the proposed algorithm.

An Ad Hoc network is a temporary network without infrastructure, dynamically formed by mobile devices without turning to any existing centralized administration. To send packets to remote nodes, a node use other nodes as intermediate relays, and ask them to transmit its packets. For this purpose, a routing protocol is needed. Because mobile devices are used, the network topology is unpredictable and can change at any time. The objective of this paper is to know the effect of mobility on the performance of Ad Hoc routing protocols, based on multi simulations performed with Glomosim.

This paper deals with application of Artificial Neural Network (ANN) for Radar Clutter rejection, function approximation method of supervised ANN is applied here using back propagation algorithm. The database used for training and testing the ANN has been collected from simulating a moving vehicle in MATALAB(version 7.9) to obtain the RCS values at range and cross-range profiles. This work is validated by comparing received signal after clutter rejection with the received signal in no clutter condition.

This paper presents a survey on recent advances in honeypot research from a review of 80+ papers on honeypots and related topics mostly published after year 2005. This paper summarizes 60 papers that had significant contribution to the field. In reviewing the literature, it became apparent that the research can be broken down into five major areas: new types of honeypots to cope with emergent new security threats, utilizing honeypot output data to improve the accuracy in threat detections, configuring honeypots to reduce the cost of maintaining honeypots as well as to improve the accuracy in threat detections, counteracting honeypot detections by attackers, and legal and ethical issues in using honeypots. Our literature reviews indicate that the advances in the first four areas reflect the recent changes in our networking environments, such as those in user demography and the ways those diverse users use new applications. Our literature reviews on legal and ethical issues in using honeypots reveals that there has not been widely accepted agreement on the legal and ethical issues about honeypots, which must be an important agenda in future honeypot research.

Steganography is the science that deals with hiding of secret data in some carrier media which may be image, audio, formatted text or video. The main idea behind this is to conceal the very existence of data. We will be dealing here with image steganography. Many algorithms have been proposed for this purpose in spatial & frequency domain. But in almost all the algorithms it has been noticed that as we embed the secret data in the image the certain characteristics or statistics of the image get disturbed. Based on these disturbed statistics steganalysts can get the reflection about the existence of secret data which they further decode with the help of available steganalytic tools. Steganalysis is a science of attacking the hidden data to get an authorized access. Although steganalysis is not a part of this work but it may be sometimes discussed as a part of literature. Even in steganography we are not purely concerned with spatial or frequency domain rather our main emphasis is on adaptive steganography or model based steganography. Adaptive steganography is not entirely a new branch of steganography rather it is based upon spatial & frequency domain with an additional layer of mathematical model. So here we will be dealing with adaptive steganography which take care about the important characteristics & statistics of the cover image well in advance to the embedding of secret data so that the disturbance of image statistics as mentioned earlier, which attracts the forgery or unauthorized access, can be minimized. In this survey we will analyze the various steganography algorithms which are based upon certain mathematical model or in other words algorithms which come under the category of model based steganography.