Digital watermarking is a special case of the general information hiding problem. It inserts a
perceptually transparent pattern called watermark in an image called host or cover using an embedding
algorithm. The purpose of the watermark is to supply the ownership of the image or copyright protection
information. The energy of the embedded data should be low enough when projected onto the human
perception domain but it should be strong enough for robust machine detection. Least Significant Bit
(LSB) technique is the earliest developed technique in watermarking and it is also the most simple, direct
and common technique. It essentially involves embedding the watermark by replacing the least significant
bit of the image data with a bit of the watermark data. The disadvantage of LSB is that it is not robust
against attacks. The aim of this study is to develop a robust watermarking model using spatial domain
technique and at the same time maintaining important watermarking requirements of picture quality. The
new model has been developed based on intermediate significant bit (ISB) aim to replace the
watermarked image pixels by new pixels that can protect the watermark data against attacks and at the
same time keeping the new pixels very close to the original pixels in order to protect the quality of
watermarked image. The technique is based on testing the value of the watermark pixel according to the
range of each bit-plane. The main contribution of this research is replacing the classic least significant bits
(LSB) technique by a new technique called intermediate significant bits ISB, which improves the
robustness and maintains the quality of watermarked images.

Watermarking technique based on ISB (Intermediate Significant Bit)

Image steganography using exploiting modification direction for compressed encrypted data

Hiding the presence of data during communication has become a pressing concern in this extremely digitalized world due to the unauthorized data access and network violations that are rapidly emerging. These concerns have led to cryptography and steganography techniques as methods for securing data. Steganography is the process of concealing confidential information in the codes that creates digital files. This paper presents a modified information-hiding technique based on indirect least significant bit hiding. Instead of saving each bit of the secret message in the Least Significant Bit (LSB) of the cover media, each bit of the secret message is compared to a specific bit in the cover media, and the result of the comparison is saved in the cover media’s LSB. In this paper, two steganography schemas are designed in which the cover media are image and audio, while the secret message is a text file. In image steganography, each channel (red, green and blue) is used to conceal the secret message; the location of the bit that is used to compare to the secret message is generated for each channel using the binary representation of the first cell for each channel. In audio steganography, the bit location for each audio sample is retrieved from the bit representation of the audio length. A simple encryption technique is used to transform the secret message into an unreadable format before the hiding process begins. The experimental results indicate that the proposed algorithm achieves promising performance in terms of the quality metrics PSNR, SNR and SSIM.

Image and audio steganography based on indirect LSB

Steganography is a way to conceal secret message under a cover image, and is one of the most widespread approaches of securing information. The challenge of steganographic methods is to find a balanced trade-off between visual quality and capacity. In addition, robustness and security are also important that need to be considered. The Least Significant Bit (LSB) insertion approach is one of the most popular steganographic techniques, which can provide both high visual quality and large capacity. However, the LSB approach suffers from robustness and security. Thus, this study proposes a new steganography approach that involves five phases: (i) RGB colour cover image is converted to YCbCr colour space. Then, Cb component is selected to hide the secret data. (ii) The secret message is encrypted by using the Affine Cipher. (iii) The encrypted message is then compressed using the Huffman Coding. (iv) The Knight Tour algorithm is applied to embed the secret code onto the Cb component using LSB approach. (v) Once completed, the Cb is merged with the Y and Cr components and is subsegueatiy converted to RGB image to obtain a stego-image. Experimental results showed that not only has the proposed method improved the security and capacity as compared to the last LSB method, it has also increased the visual quality of the stego-image.

Alla Talib Mohsin

Papers

A new steganography technique using knight’s tour algorithm, affine cipher and huffman coding