Study On Data Hiding Algorithms Based On Compression Codes

With the rapid development of network techniques, Internet has been the most popular way to access information and knowledge. The new multimedia techniques make information transmission and communication more direct and simple. The huge amounts of information in the form of test, image, audio or video requires a wider network bandwidth. Compression data before transmission to reduce data size as well as transmitting the shorter compression codes is a better way. However, information transmission is in the danger of replication, tampering, and damage. For some sensitive fields such as medical, military and artwork, it’s an urgent issue to strengthen the security of transmission.The main content of this paper is as follows:(1) A high performance reversible data hiding based on LZW codes is proposed. We adopt the relationship of LZW codes and dictionary size to embed message. The experimental results show that our scheme achieves high embedding capacity and fast embedding and extracting speeds due to the simple operation.(2) Lossless VQ indices compression method based on the high correlation of adjacent image blocks is proposed. This method divides images into blocks, and encodes them with VQ indices. The high correlation of adjacent images blocks is exploited to match the same index on the search path and in the state codebooks. The results reveal that the bit rate is promoted significantly with good visual quality.(3) A novel watermark scheme for calligraphy images is proposed. In this scheme, the complex region of images are used to embed watermark according to the VQ encoding methods and the predetermined rules, while the smooth region maintains unchanged to lower image distortion. The experimental results show that this scheme realizes good robustness and high embedding capacity.The first method modifies the LZW compression codes directly and embeds information reversibly; the second method further compresses the VQ index table, thus increasing the embeddable space; the third scheme achieves authentication function by embedding watermark according to the characteristic of the calligraphy images. Above all, this paper focuses on information hiding algorithms based on compression codes from the discipline, the optimization, and specific source files of compression algorithms.