Design And Implementation Of Digital Steganography Image Acquisition System Based On Web Crawler

As a new information hiding technology, coverless information hiding has become one of the hotspots in the field of information hiding in recent years. The important features of image-based coverless information hiding is to build the mapping relationship between images and the hidden information, that is, to construct images including secret messages to achieve information hiding without modifying the original images. In order to further prevent from attack and analysis, coverless information hiding technology usually uses something popular as carriers, for instance, the hot images on the Internet,which are distributed in every corner of the Internet, and are generally attached to Internet text messages, such as popular news, popular microblogging, etc. Therefore,how to collect popular images from Internet effectively has become an important problem of coverless information hidding technology.At present, web crawler is recognized as one of the most effective tools among lots of functional modules in accordance with the specific strategy of continuous resource extraction and collection.If there exists logical irrationality in terms of content in the selected images, a secret message expressed by a combination of these images may suffer from doubts and attacks from non-cooperative parties easily, which violates the critical principle of less suspicion. Thus, the combination of images must be logical, reasonable in content, namely the set of images that are content relative should be selected as alternative images, and this will involve the similarity calculation and retrieval of images .This paper designs and implements a popular image acquisition system based on the technology of theme web crawler, web page information extraction, document weighting,retrieval and so on, and builds a complete set of images for the coverless information hiding.The popular image acquisition system implemented in this paper includes a web page acquisition module, a web page information extraction and analysis module, an image retrieval module. The web page information collection module expand the Heritrix reptile, and responsible for collecting the site of the site; Web page information extraction analysis module makes full use of extraction templates and Jsoup parser to extract the required information from the page, weight the page, and then calculate the hot news;Image retrieval module utilize the Lucene indexing tool to create index of the color characteristics and texture features,to achieve the retrieval of image similarity. This paper analyzes the realization mechanism of each module, and uses the corresponding development tools to realize the various modules. From the measured results, the popular image acquisition system designed by the paper can collect the popular images automatically and logically, and create index for the collected images according to the basic characteristics of the image, which can meet the needs of the actual project.