The Research Of Image Encryption Engineering Based On Visual Model

With the rapid development of computer technology and the wide application of internet in recent years, many digital creations and achievements are easily to be illegal copied, forged and tampered. As the result, copyright holders do not want to disclose their works through the internet, which is detrimental to the development of digital creations. At present, the copyright protection of digital creations is not only legislation, but also a important technical problem. To the point of technology, the insertion and the detection of digital media copyright information are the two key issues of copyright protection of digital creations. Besides the request of Stability, it combines the characteristics of authentication and identification from traditional cryptography. Copyright protection information must be closely integrated with the data which are protected. Therefore, identification process of copyright protection information should possess anti-jamming capability. And digital watermarking emerged. In order to prevent pirating and tampering of digital products, it provides complete and reliable evidence for the integrity and ownership of media data, which are protected by copyright, through embedding some important information into it.This article provides some interesting watermarking algorithm based on visual pattern. Some works have done as followed:(1) A loss compression resisting public watermarking technique was presented. A watermark with visually recognizable pattern was embedded into the host image by modifying the polarity between DC value and low-frequency Ac value in each DCT block, and the watermark was adapted to the image by utilizing the masking characteristices of HVS.(2) In order to improve the accuracy of the relevance of traditional detection, embed two unrelated pseudo-random sequences when embed watermark, which can greatly improve the accuracy of detection. Revising low-frequency part is easily to cause the distortion. Because most of the energy of the image is concentrated here, embedding through revising high-frequency part is introduced in this article.(3) The method of watermark detection introduced in this article is semi-blind, which only need part of the original watermark information. And therefore, it has a important practical significance.