Robust and secured data hiding schemes using digital image steganography

Abstract

Transmitting data over a public network such as the Internet necessitates increasing the security of data communications; especially with the highly sensitive document transfer. Steganography techniques have been introduced and developed to provide security to these applications. Fundamentally, the steganography goal is not only to hinder the adversary from decoding a hidden message, but also to prevent an adversary from suspecting the existence of covert communications. It does not replace cryptography but rather improves the security using its obscurity features. If one's suspicious is raised while using a steganography technique, the goal of the latter will be defeated regardless whether or not a plaintext is revealed. In this research, two steganography techniques for digital images were developed. The first algorithm provides a new and efficient steganographic system, called Characteristic Region-Based Image Steganography (CR-BIS). It combines both the robustness of Speeded-Up Robust Features technique (SURF) and Discrete Wavelet Transform (DWT) to achieve characteristic region steganography synchronization. It avoids hiding data in the whole image by dynamically selecting characteristic regions for the process of embedding. Such a dynamic manner of region selection increases the security of embedded data. The experimental results showed that CR-BIS provided stego-images with a good perceptual quality; this was indicated by the obtained high Peak Signal to Noise Ratio (PSNR) values, up to 48.30 dB. The second algorithm, namely, an Improved Robust and Secured Steganography (IRSS), is an improvement of Mali et al.’s algorithm, which has a reliability defect as some data cannot be retrieved at the extraction phase. IRSS has overcome the problem of information loss via adopting the concept of the embedding map. Besides, it has been proved experimentally that IRSS outperformed the original one in terms of stego-image quality; this was demonstrated by the achieved PSNR values, which were between (37.28-39.74) dB. In the two proposed algorithms, the embedded secret information can be correctly recovered without referring to the original cover-image. In addition, improving the robustness of the stego-system by Error Correcting Codes (ECC) insertion and adding redundancy bits to the secret embedded message is defined and evaluated, in order to suggest an appropriate robustness enhancing method for the proposed algorithms. As a popular ECC, Reed- Solomon Code (RS-Code) was used to produce correction bits equal to the number of bits produced by a specific redundancy factor. It has been concluded from the experimental results that RS-code improved the robustness of CR-BIS algorithm more than the addition of redundancy does. On the other hand, adding redundancy bits to the message has a much better effect on the robustness of IRSS algorithm.