The Spatial Domain Steganography Of Digital Image Information Hiding

With the rapid development of modern network technology and the greatly improved computing capabilities, the limitations of conventional cryptography are increasingly apparent. Information hiding is a new and emerging technology that proposed in this context, Steganography is an important branch of information hiding, The purpose of Steganography is to hide the fact that "are communicating, Steganography embeds secret information into the image, audio and other digital media vector, and then it carries secret information through public communication channel, especially the internet. Therefore, the main requirement of steganography is good imperceptibility and extents to its largest embedding capacity. Currently, the embedding capacity of steganographic algorithm that is based on spatial domain has great advantages than other algorithms; therefore it has become the mainstream of steganography algorithms. Meanwhile, digital image has become the preferred carrier of steganography by large amount of information, facilitate of processing and transmission, wide range of applications.The Domestic and foreign status quo of Information hiding and Steganography has been summerized in this paper. This paper also researches the type and evaluation methods of digital image carrier, analyzes several classical steganographic algorithm which have important position in the field of digital image steganography, introduces two key issues in steganographic:First, the consideration of human visual system; Second, the segmentation of image block processing. Derived from the above principal, this paper proposes two new steganographic algorithm based on digital image and spatial domain.(1)In order to compensate the defect of Side Match algorithm and improve the capacity of hidden secret date, this paper presents a image steganographic method based on Side Match and LSB replacement. According to Human Visual System, the method divides an image into smooth areas, transition areas, and edged areas by the difference value of neighboring pixels. It uses different bits LSB substitution in three areas above. Experimental results show that the proposed method provides larger embedding capacity and maintains a high visual quality of stego—image, the defect of Side Match algorithm has also been fixed.(2)Tri-way Pixel-Value (TPVD)-based steganography underestimates the embedding capacity of smooth areas. Based on this, this paper proposed a large capacity steganographic scheme based on TPVD. According to Human Visual System, this method uses3bits LSB substitution in smooth areas blocks and uses TPVD steganographic algorithm in edged area blocks. Experiment results show that steganography has a larger embedding capacity and maintained a better steganographic performance than TPVD algorithm in the premise of controllable high visual quality of stego-image.