Rupali Bhardwaj

An Overview on Tools for Peer to Peer Network Simulation

is an attempt to model a system in order to study it scientifically. Simulations are the most popular tool for examine peer-to-peer (P2P) applications. The cost of implementation of simulated model is less than that of large-scale experiments and, if carefully constructed, the simulated model can be more realistic than any tractable mathematical model. Simulating P2P overlay networks is a common problem for researchers and developers because P2P systems can consist of million of nodes and dynamic in nature. So that simulation for such a large dynamic network is difficult due to technical constraints even on the most powerful machines. In this paper we focus on various available P2P simulators and summarized them against a proposed set of attributes such as scalability, architecture language and pros and cons of each simulator.

A propound method for agent based dynamic load balancing algorithm for heterogeneous P2P systems

In peer to peer (P2P) systems agent based load balancing is one of the most important problem. P2P systems are characterized by decentralization, scalability and dynamicity, such that they can been seen as instances of complex adaptive systems (CAS). In this paper we present ant-based load balancing algorithm, which effectively balances loads of peers distributed among P2P systems with the help of autonomous agents called Ants. Ants search a pair of overloaded and underloaded nodes through wandering on network and transfer tasks from different overloaded nodes to different underloaded nodes simultaneously. It is assumed that time break that ants spend on searching a pair of overloaded, underloaded node and transfer of virtual servers between them is negligible. The algorithm developed increases response time of submitted jobs and decreases communication overhead by load transfer in terms of virtual servers between overloaded and underloaded nodes simultaneously.

Enhanced the security of image steganography through image encryption

Steganography and Cryptography are two integral parts of information security. Cryptography is the science of using mathematics to encrypt and decrypt data; the data are converted into some other gibberish form, and then the encrypted data are transmitted. Steganography is the art of hidden communications, encoding/embedding hidden information in cover media in such a way so as not to provoke an eavesdroppers suspicion. If a message is encrypted and hidden with a steganographic method it provides an additional layer of protection and reduces the chance of the hidden message being detected. The primary purpose of this paper is to provide two levels of security through a two step process, rather than hidden the message bits directly in cover image, they are scrambled in a random order generated by 2D Arnold Cat Map after that encrypted message is hidden behind a cover image using basic LSB method. MSE (Mean Square Error) and PSNR (Peak Signal to Noise Ratio) are two common quality measurements to measure the difference between the cover-image and the stego-image. Results showed that the proposed method gives better results than simple LSB with higher PSNR and lower MSE.

Effective Image Encryption Technique Through 2D Cellular Automata

Basic idea of encryption is to encrypt the pixels of an image in such a manner that the image becomes chaotic and indistinguishable. In this paper, we have done exploratory study on image encryption techniques through 2D cellular automata (single layer and double layer) which create chaos on pixels of considered image. A comparative analysis on effectiveness of scrambling technique is provided by scrambling degree measurement parameters, i.e., gray difference degree (GDD) and correlation coefficient. Experimental results showed that the 2D cellular automata (single layer)-based encryption gives better result than 2D cellular automata (double layer).

Cellular Automata: Elementary Cellular Automata

Cellular automata CA are discrete dynamical systems consist of a regular finite grid of cell; each cell encapsulating an equal portion of the state, and arranged spatially in a regular fashion to form an n-dimensional lattice. A cellular automata is like computers, data represented by initial configurations which is processed by time evolution to produce output. This paper is an empirical study of elementary cellular automata which includes concepts of rule equivalence, evolution of cellular automata and classification of cellular automata. In addition, explanation of behaviour of cellular automata is revealed through example.

Multimedia Security through LSB Matching

Steganography is the art of hidden communications, encoding/embedding hidden information in cover media in such a way so as not to provoke an eavesdroppers suspicion. In this paper, we propose an efficient image steganography technique which provides high embedding capacity as well as imperceptibility of stego image. Using fixed number (i.e. two) as the upper limit criteria for embedding, the target pixel, based on equality between pixel bits and secret data bits is selected for embedding. As an indicator to determine which pixel is used for embedding, least significant bit is reversed. The experimental results showed preserving stego image quality with ability of embedding high data capacity. Results showed that the proposed method gives better results than simple LSB and inverted LSB with higher PSNR and lower MSE.

Image forgery detection using QR method based on one dimensional cellular automata

This paper tries to provide a reliable scheme for the image forgery detection. QR Decomposition is applied on the original image to extract the features of the image and then Robust Secret Key is generated by pushing those features into the cellular automata. QR Decomposition is used to decompose the image into two matrices namely orthogonal and upper triangular matrix. Robust Secret Key is used to protect the images against forgery. Our scheme is tested on images of size 512 × 512 and experimental results are compared with the existing techniques to illustrate the visual quality, robustness and reliability of the proposed scheme

A lossless Data Hiding method based on inverted LSB technique

Reversible Data Hiding is the technique of concealing covert information in cover media to ease secure communication without compromising the quality of cover media after extracting the message. The primary purpose of this paper is to implement RDH by generating a blueprint of the cover image, in which complemented message is hidden using inverted bit LSB [1] technique. Results prove that proposed method show improvement of higher PSNR and lower MSE.