Biswapati Jana

Cheating prevention in Visual Cryptography using steganographic scheme

Visual Cryptography (VC) is a technique to encrypt a secret image into transparent shares such that stacking a sufficient number of shares reveals the secret image without any computation. Cheating is possible in the Visual Cryptographic Schemes (VCS) by dishonest or malicious participant called a cheater, may provide a Fake Share (FS) to cheat the other participants. To achieve cheating prevention in VC we have proposed a steganographic scheme to embed a secret message in each of the shares in random location during share generation phase called stego share. Before stacking receiver can extract hidden message from stego share for checking authentication of shares. In this method no verification share is required to prevent cheating in VC.

Dual image based reversible data hiding scheme using (7,4) hamming code

In this paper, we propose a new dual-image based reversible data hiding scheme through (7,4) Hamming code (RDHHC) using shared secret key. A block of seven pixels are collected from cover image and copied into two arrays then it is adjusted redundant Least Significant Bits (LSBs) using odd parity such that any error creation is encountered at the sender end and recovered at the receiver end. Before data embedding, we first complement the bit at shared secret position. After that, secret message bit is embedded by error creation caused by tamper in any suitable position except secret position and that error is detected as well as corrected at the receiver end using Hamming error correcting code. One shared secret position κ and one shared secret key ξ help to perform data embedding, data extraction and recovery of the original image. The secret data and original cover image are successfully recovered at the receiver end from dual stego image. Finally, we compare our scheme with other state-of-the-art methods and obtain reasonably better performance in terms of PSNR.

Object Extraction Using Novel Region Merging and Multidimensional Features

Understanding natural images is a difficult task. One method to accomplish that can be, first, segment the image into regions of similar characteristics and then apply some object extraction scheme. Alternatively, extraction of characteristics of the desired objects can be initiated at the beginning. In this paper, we propose a scheme that adopts the former approach. An image is first segmented and then a novel region processing algorithm is applied. It is found that the proposed algorithm is capable of removing a high percentage of insignificant regions. Following region processing, a multidimensional feature extraction scheme is used. A set of five primitive and non-primitive features are used to create the feature vectors. The image dataset is divided into two parts, i.e. training and test sets. Results show the effectiveness of the proposed feature vector in extracting known objects present in natural and specific domain images.

Partial reversible data hiding scheme using (7, 4) hamming code

In this paper, we propose a partial reversible data hiding scheme using (7,4) Hamming code (PRDHHC) with secret position (κ). In this scheme, we partition the original cover image into (7 × 7) pixel block and adjust redundant LSB bits of each row using odd parity. Then we calculate secret position κ = (δ mod 7) + 1, where δ is a shared secret key. The bit at position κ and a suitable location for hidden message bit is modified through error creation caused by tamper in each row of the selected block. For the next row, the κ is updated by the data embedding position (ω) of the previous row. We repeat this process to embed secret message bits within the selected block. For each new block, the κ is updated by κi+1 = (κi × δ × ω) mod 7 + 1, where i = 0, 1, 2, 3, . . . , number of blocks. At the receiver end, we complement the bit at position κ then retrieve the secret message bit by applying Hamming error correcting code. The extraction process will be stopped when we find continuous no error within stego image. The propose PRDHHC scheme extract the hidden message successfully and recover hamming adjusted cover image by complement bits at both the κ and ω positions but can not recover original cover image, that is to say, our scheme is partial reversible. Finally, we compared our scheme with other state-of-the-art methods and obtained reasonably better performance in terms of visual quality (measured by PSNR). Also we analyze our generated stego image using some steganalysis techniques which give promising results.

Reversible Watermarking Scheme Using PVD-DE

A new reversible watermarking scheme has been proposed using PVD and DE scheme. Here, two copies of watermarked images are generated after embedding watermark within cover work. The logo image is used as watermark for image authentication and message digest calculated from cover image is used for tampered detection. Four bits authentication code are embedded using Pixel Value Difference (PVD) within two consecutive pixels and one bit tampered detection code is embedded using Difference Expansion (DE) method within same pixel pair. After embedding watermark, two sets of watermarked pixel pair has been generated. Now, we distribute two watermarked pixel pair among dual watermarked image depending on a shared secret key. At the receiver end the authentication code and message digest are successfully extracted using PVD and DE from dual watermarked image. The scheme is reversible because it can recover original cover image from dual watermarked image after extraction the watermark. Finally, it has been compared with existing state-of-the-art methods and obtained reasonable better results in terms of capacity and quality measured by bpp (bits per pixel) and PSNR (Peak signal to noise ratio) respectively.

Hierarchical Visual Secret Sharing Scheme Using Steganography

The rapid growth of computer networks and technology constructs a favorable environment that can tolerate the multiusers in a hierarchy based. In any organization the personnel are frequently organized in the form of a hierarchy and there is the requirement that information is distributed over the hierarchy on a “need-to-know” basis. In this paper, we propose a new hierarchical visual secret sharing scheme, where steganographic technique has been used to maintain hierarchy and detect fake share using weight matrix-based embedding method. In this approach, we have used a key matrix (K) and a weight matrix (W) to hide critical information (M) into the share on each level of our proposed scheme. The basic ideas are: (i) to use an EXclusive-OR operator to protect the key matrix (K) and (ii) to use a weight matrix (W) to increase the data hiding rate while maintaining high quality of the share image in each level in hierarchy of the scheme. The share generator or Trusted Authority (TA) generates weight matrix \(W_i\) for share \(S_i\) and each level modifies weight matrix \(W_{i+1}\) using the formula Open image in new window where \(i=0, 1, 2,\ldots , n\) to keep track of level and maintain the hierarchical structure in proposed scheme. The experimental results are demonstrated and tested using Peak Signal-to-Noise Ratio (PSNR) value and relative entropy. It shows that our scheme is superior in terms of PSNR compared to existing schemes.

A Cryptosystem for Encryption and Decryption of Long Confidential Messages

In this paper, we propose a cryptosystem which can encrypt and decrypt long (text) messages in efficient manner. The proposed cryptosystem is a combination of symmetric-key and asymmetric-key cryptography, where asymmetric-key cryptography is used to transmit the secret key to an intended receiver and the sender/receiver encrypts/decrypts messages using that secret key. In 2002, Hwang et al. proposed a scheme for encrypting long messages. The main drawback of their scheme is that it requires more computational overhead. Our proposed scheme is more efficient from the computational point of view compared to that of their scheme. Our scheme is a block cipher, long messages are broken into fixed length plaintext blocks for encryption. It supports parallel computation, since encryption/decryption of all the blocks of plaintext/plaintext are independent and thus can be carried out simultaneously. In addition, our scheme retains the same security level as their scheme.

Reversible data hiding scheme using sub-sampled image exploiting Lagrange’s interpolating polynomial

In this paper, a new reversible data hiding scheme has been proposed using lagrange’s interpolating polynomial on interpolated sub-sampled images. First, we generate sub-sampled images from original image and enlarge its size using image interpolation. Now, we convert secret message using lagrange interpolating polynomial and generate new secret message. The new secret message is divided and stored within interleaved pixel of each interpolated sub-sampled images. At the receiver end, new secret message is extracted from interleaved pixel of each sub-sampled stego images and then lagrange’s interpolation is applied to generate original secret message. The security has been enhanced due to the distributive nature of hidden data within multiple images. The original pixels are not effected during data embedding which assure reversibility. The proposed scheme provides average embedding capacity with good visual quality measured by peak signal to noise ratio (PSNR) which is greater than 50 dB. It is observed that the proposed scheme provides better performance than other existing data hiding schemes in terms of data embedding capacity, visual quality and security. We have analyzed our stego images through RS analysis, calculate relative entropy, standard deviation and correlation coefficient of original and stego image to show the robustness under various steganographic attacks.

An Efficient Data Hiding Scheme using Hamming Error Correcting Code

In this paper, we propose an efficient secure partially reversible data hiding scheme using hamming error correcting code (PRDHHC). Recently, Kim et al. proposed a data hiding technique in halftone image which hides four secret bits within (4 x 4) image block through codeword. Lien et al. presented data hiding scheme using hamming code by generating dispersed block through space filling curve decomposition using fifteen bits codeword. Here, we propose data hiding scheme through error creation in three least significant bits of a (7 x 7) image block using shared secret key. During extraction, the receiver finds the error position within three least significant bits of the image block and extracts secret data with the help of shared secret key. After extraction, we complement the error bits to achieve partial reversible data hiding. Our scheme is compared with other state-of-the-art methods and we obtain reasonably good performance in terms of PSNR and embedding capacity.

A New Dual Image-Based Steganographic Scheme for Authentication and Tampered Detection Using (7, 4) Hamming Code

Here we proposed an efficient dual image-based reversible steganographic technique using (7,4) Hamming code for image authentication and tampered detection. In this approach, the cover image is partitioned into \((1 \times 7)\) pixel blocks. The blocks are copied into two separate images, and three Least Significant Bits (LSB) are collected from each block separately. Then perform odd parity adjustment using Hamming code. Two symmetry keys \(\kappa \) and \(\xi \) are used for data embedding and stego block distribution among dual images, respectively. To embed secret bit complement data bit at \(\kappa \) position, then secret data bit is embedded through error creation at random positions within the block excluding the position of \(\kappa \) such that errors are corrected and cover image is recovered through (7,4) Hamming code. The proposed scheme has been verified through experimental results with existing scheme. The performance of this scheme is comparatively better in terms of visual quality. The experimental results showed that this new steganographic technique can be also applied for authentication and tampered detection.