期刊名称：BVICAM's International Journal of Information Technology
印刷版ISSN：0973-5658
出版年度：2009
卷号：1
期号：1
出版社：Bharati Vidyapeeth's Institute of Computer Applications and Management
摘要：Steganography has been an important subject since people started communicating in writing. Steganography means hiding a secret message (the embedded message) within a larger one (source cover) in such a way that an observer cannot detect the presence of contents of the hidden message. Today the growth in the information technology, especially in computer networks such as Internet, Mobile communication, and Digital Multimedia applications such as Digital camera, handset video etc. has opened new opportunities in scientific and commercial applications. But this progress has also led to many serious problems such as hacking, duplications and malevolent usage of digital information. Steganography finds its role in attempt to address these growing concerns. We know that, with the use of steganographic techniques, it is possible to hide information within digital audio, images and video files which is perceptually and statistically undetectable. The method of embedding secret message (which can be plain text, cipher text, or even images) is usually based on replacing bits of useless or unused data in the source cover (can be audio files, sound, text, Disk space, hidden partition, network packets, digital images, software, or circuitry). There are two common methods of embedding: Spatial embedding in which messages are inserted into the LSBs of image pixels, and Transform embedding in which a message is embedded by modifying frequency coefficients of the cover image (result is called the stego-image).Transform embedding methods are found to be in general more robust than the Spatial embedding methods which are susceptible to image-processing type of attacks. However with respect to steganography robustness is not a critical property but the perceptibility (i.e., whether the source cover is distorted by embedding information to a visually unacceptable level). There is another important issue of steganography, namely, capacity, i.e., how much information can be embedded relative to its perceptibility [5, 1].?
