Reversible data hiding in encrypted images (RDH-EI) has attracted various communities that deal with security. Xiao et al. presented RDH-EI that uses pixel value ordering (PVO) and additive homomorphism for encryption ensuring that the embedding capacity of plain and encrypted image remains relatively same. However, the size of location map required to manage over/under flow blocks increased drastically reducing the overall embedding capacity. In the paper, a new PVO-based separable RDH scheme is proposed using double encryption. The original image is encrypted using chaotic mapping in Phase 1, ensuring that the performance of PVO algorithm in an encrypted domain is similar to that in plain domain. Secret data is embedded in this encrypted image. The embedded image is re-encrypted using additive homomorphism to enhance security. The proposed scheme is more efficient as it improves the pure embedding rate and total embedding capacity of the image by reducing location map size, overcoming the drawback of Xiao et al.

Grid environment is a virtual organization with varied resources from different administrative domains; it raises the requirement of a secure and reliable protocol for secure communication among various users and servers. The protocol should guarantee that an attacker or an unidentified resource will not breach or forward the information. For secure communication among members of a grid group, an authenticated message transferring system should be implemented. The key objective of this system is to provide a secure transferring path between a sender and its authenticated group members. In recent times, many researchers have proposed various steganographic techniques for secure message communications. This paper proposes a new secure message broadcasting system to hide the messages in such a way that an attacker cannot sense the existence of messages. In the proposed system, the authors use steganography and image encryption to hide group keys and secret messages using group keys in images for secure message broadcasting. The proposed system can withstand against conspiracy attack, message modification attack and various other security attacks. Thus, the proposed system is secure and reliable for message broadcasting.

Data hiding is an emerging field of research for secure data transmission over internet, ensuring ownership identification and copyright protection. A couple of techniques have been proposed based on pixel value differencing (PVD) and eight queens' solutions. In this paper, a new data hiding method based on inter-block difference in eight queen's solutions is presented. The result of inter-block difference is XORED with ASCII code of character from the message and the resultant value is embedded in LSB position. The presented approach is more efficient and it provides a more capacity with good imperceptibility. The approach supports different digital image file formats such as bmp, png and tiff.

The quantification and prediction of inter-agent dependency requirements is one of the main concerns in Agent Oriented Requirements Engineering. To quantify and envisage exertion load of an agent within resource constraints, this work provides a comparative analysis of Sugeno and Mamdani Inference Systems. The Mamdani Fuzzy Inference System (MFIS) goes well with the vagueness and ambiguity involved with inputs and output variables-whereas the Sugeno Fuzzy Inference System (SFIS) facilitates the linear relationship between inputs and output variables that is likely to assist the developer in tailoring the values of input domain attributes to obtain required level of DoD so as to develop Multi-Agent System (MAS) of high quality. The performance of these Inference Systems is examined by means of mean execution time. The results show that the SFIS outperforms MFIS. A sensitive analysis is employed to observe the behavior of MFIS and SFIS with respect to membership functions (MFs) viz. Guassian, Triangular and Trapezodial. The equivalence of the results is measured using performance indicators-Coefficient of Correlation (CORR) and the Normalized Root Mean Square Error (NRMSE). It is observed that MFIS in comparison to SFIS appears to be sensitive to the MFs. An adaptability analysis is augmented to illustrate the distinguished behaviors of the Inference Systems with respect to the frequent variations in input data. The results show that employing a SFIS could be a good option to quantify and customize dependency requirements in inter-agent communication.

The 8-queens problem of placing 8 non-attacking queens on an 8x8 chessboard is used to hide message in an image. The method helps in randomizing the bit selection in a cover image for hiding purpose. Cover image is divided into blocks of 8x1 bytes and then masked with solutions of the 8-queens problem. Bits from the block are collected corresponding to the 8-queen solution to make a 7 bit string. LSB of the block is not considered. It gives a number in the range of 0 to 127. If a bit string, corresponding to the 8-queens solutions, matches with ASCII code of the first character from message, the corresponding solution number of the 8-queens problem is encrypted using RC4, and the cipher is stored in first block of the cover. This encrypted value works as key. The solution number corresponding to next character is XORED with the key and the resultant value is embedded in the LSB of next block. The algorithm has been tested with cover of different image file formats like BMP, PNG and TIFF. The algorithm provides very good capacity, imperceptibility and robustness.

In this paper, an algorithm to embed information in a map along Hamiltonian path is presented. A file based data structure in which a graph is treated as a composition of three components, node, segment and intermediate points that constitute a segment, is used to store a graph. In a map with N nodes, each node can represent ?log2N? bits from message bit strings. Any bits (= 0) from message between bit strings represented by adjacent nodes are embedded in a segment. In the case of a multi graph, a segment is selected based on the last two bits in the nodes. A pre Hamiltonian path is determined in the map starting from node represented by the first ?log2N? bits from message string to the last bit string ?log2N?. The method is tested on different maps and messages of different sizes and robust results have been observed. Retrieval is based on the key (S, |m|, ?) and traversing along the pre Hamiltonian path starting from node S.