Bidyut Jyoti Saha

Non blind watermarking technique using enhanced one time pad in DWT domain

The unlimited growth in internet and multimedia leads to large usage of images resulting in huge storage and distribution of multimedia contents. With increasing use of digital transmission techniques the potential risks for multimedia content is high which lead to necessity of protection for authenticity and confidentiality. To protect the confidentiality, one time pad is supposed to be the most secure algorithm. This paper proposes a secure algorithm to protect the watermark image over a public network in digital watermarking and is embedded in Discrete Wavelet Transformation (DWT). The unique key same as size of watermark is generated from the cover image. One time pad is applied using generated unique key to encrypt the watermark image. The encrypted image so formed is embedded into cover image in DWT domain. The experimental results show the effectiveness and robustness of the algorithm using PSNR and NC calculations.

Robust watermarking technique using Arnold's transformation and RSA in discrete wavelets

Copyright protection is a major concern in digital data transmission over public channel. For copyright protection, watermarking technique is extensively used. A robust watermarking scheme using Arnolds transformation and RSA algorithm in the DWT domain has been proposed in our paper. The combined encryption has been taken to provide more security to the watermark before the embedding phase. The PSNR value shows the difference between original cover and embedded cover is minimal. Similarly, NC values show the robustness and resistance capability of the proposed technique from the common attacks such as JPEG compression, scaling etc. Thus, this combined version of Arnolds transformation and RSA algorithm can be used in case of higher security requirement of the watermark signal.

Blind digital watermarking algorithm based on DCT domain and fractal images

Multimedia distribution across public network and internet is growing fast. With diverse evolution in technology of distribution and storage, various factors are challenging multimedia and internet technologies. Digital watermarking solves the problems of several threats and protects the digital data from being compromised or altered. It also provides copyright protection to avoid illegal modification of digital data. In this paper we have proposed a blind digital watermarking algorithm based on fractal images on Discrete Cosine Transform (DCT) domain. The fractal code is converted to its respected binary images and used as a watermark image. The cover image is decomposed to its respective grayscale equivalents of RGB components. The fractal codes as watermark binary images are embedded into grayscale equivalent of RGB components of cover image. The embedding is done in mid frequency to secure the codes from several attacks. The robustness and imperceptibility of the algorithm is shown in results and analysis.

Comparative study of image encryption using 2D chaotic map

Securing digital image during transmission is very much important in the current era. For this purpose, cryptographic techniques as well as chaotic maps can be applicable. In this paper, we have given a detailed study of the image encryption using different 2D chaotic maps such as Arnold 2D cat map, Baker map, Henon map, Cross chaos map and 2D logistic map. The security analysis of these techniques has been done by the help of NPCR (Number of Pixels Change Rate) and UACI (Unified Average Changing Intensity) values. The experimental results of NPCR and UACI show the effectiveness of the encryption processes of different techniques.

Enhanced digital watermarking scheme using fractal images in wavelets

Digital communication is under risk due to different types of attacks on its confidentiality, integrity and authenticity. Copyright information need to be protected to preserve owners information over untrusted network. Innovation in technology is also bringing challenges to secure the originality of owner information. Digital watermarking comes as a solution to protect and secure the owners information through the means of different embedding technique to avoid security risks and threats. Our paper proposed a technique to embed fractal images in Discrete Wavelet Transform (DWT). The binary watermark image is generated from fractal codes. The color cover image is decomposed to its grayscale equivalents. The grayscale equivalents of color image are used to embed the watermark image which is generated from fractal codes in mid frequency blocks to protect the codes from attacker. Same watermark images are embedded into grayscale equivalents separately to increase the robustness and security of the scheme. The result analysis shows the robustness and imperceptibility of the algorithm.

Comparative analysis of digital watermarking scheme using enhanced playfair cipher in DCT & DWT

During past few decades, communication over internet increased to transfer digital data across worldwide. The development of communication media over untrusted network bring lot of challenges for the developers. The algorithms and techniques should be robust, complex, and secure as well as ease of use and implementation in order to secure digital content over from potential risk and threats. In this paper, we have compared new encryption techniques as a preprocessing step for digital watermarking in Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) using the basics of playfair cipher. The proposed preprocessing step is implemented in different transform domain techniques to find the robust and secure way to embed ownership details in a cover media. The watermark image is encrypted using modified playfair cipher to form encrypted image which is further hidden in host media using DCT and DWT. The comparisons between different approaches are analyzed with the encrypted watermark information. The results and analysis show the robustness and security of these algorithms.

A robust digital watermarking algorithm using DES and ECC in DCT domain for color images

Nowadays, Internet and multimedia is popularly growing fast and is being used in digital communication. With increase in demand, risks are also involved. Thus, digital watermarking is an absolute method to provide authentication and copyright protection to the digital media to protect it from illegal modification and redistribution. In this paper, we have proposed a robust watermarking algorithm using DES, ECC and DCT for color images. The original color image (watermark) and cover image has been separated into three independent color channels (red, green and blue) and their gray scale equivalents are used. Each individual gray scale equivalent of RGB components of original image has been encrypted using Data Encryption Standard (DES). The Henon map is used to generate three different round keys for DES with different initial parameters. After encrypting three different gray scale equivalents, the encrypted images are mapped to the points of elliptic curve. The mapped images so formed are embedded in different gray scale equivalents of RGB components of color image using DCT. The mapped images are hidden into the mid frequency of DCT blocks to avoid it from common attacks. The effectiveness and robustness of the algorithm is shown in the experiments.