information hiding, which can be traced back to 1499, has a long history. However, IT was not until the 199s that people gave it new content in the IT field, making it another powerful tool to protect information after encryption technology. The obvious difference between information hiding and traditional information encryption is that the traditional encryption technology aims at hiding the content of information, which makes the encrypted file difficult to understand, while information hiding aims at hiding the existence of secret information. Therefore, with the development of science and technology, information hiding technology has become a new research hotspot in the information age. It not only carries forward the advantages of traditional hiding technology, but also has modern unique characteristics. For scholars who study the direction of information security, it is significant and urgent to study information hiding.
Related research on information hiding
In the research of information hiding, we mainly study information hiding algorithm and covert communication. Among the information hiding algorithms, there are mainly spatial domain algorithm and transform domain algorithm. The most typical spatial information hiding algorithm is LSB algorithm, and the most typical transform domain algorithm is wavelet transform algorithm. Because of the poor robustness of LSB algorithm, the related research and improvement work is to improve its robustness. As for the wavelet transform algorithm, because wavelet transform has good local characteristics of video, and JPEG2 and MPEG4 compression standards have achieved higher compression rate by using wavelet transform algorithm, the information hiding technology based on wavelet transform has become a hot research topic at present. Generally, according to human visual characteristics, secret information is compressed by wavelet in a certain proportion, and the compression process increases the embedding capacity of data. Then the wavelet coefficients are quantized and converted into binary stream data. The carrier signal is also subjected to wavelet transform, and appropriate wavelet coefficients and embedding parameters are selected to embed information. Because there are dozens of wavelets, and the characteristics of each wavelet are different, the selection of parameters is also different. Therefore, it is necessary to screen out the methods with good concealment and large capacity through experiments, so as to balance the imperceptibility, robustness and capacity. In addition, it is also possible to replace the average value of the wavelet coefficients of even points and the wavelet coefficients of two adjacent points, which is called interpolation, as the location where the secret data is embedded.
Implementation stage of information hiding
Generally speaking, information hiding is divided into four stages: preprocessing stage, embedding stage, transmission stage and extraction stage. In order to make each stage secure, it is necessary to introduce the encryption algorithm in encryption in the preprocessing stage. In the embedding stage, the algorithm of hiding information based on wavelet is used, and in the transmission stage, covert communication is carried out, so it is also safe to use the transmission stage. Therefore, this set of information hiding processing scheme will form a secure system, so it can not only hide the content of secret information, but also hide the receiver and sender of communication, thus establishing hidden communication.
Application scope of information hiding
The advantages of information hiding determine that it has a wide application prospect, and its application scope includes: electronic transaction protection, secure communication, copyright protection, copy control and operation tracking, authentication and signature in e-commerce. Information hiding is mainly divided into steganography and digital watermarking. Digital watermarking technology is mainly used for copyright protection, copy control and operation tracking. In copyright protection, copyright information is embedded into multimedia (including images, audio, video and text) to achieve identification, annotation and copyright protection. The application of digital watermarking technology has been very mature. Another branch of information hiding is steganography, and the classification of steganography is based on different reasons: it can be classified according to the structure of steganography system: pure steganography, key steganography and public key steganography; According to the classification of steganography space: it can be divided into channel steganography, spatial steganography and transform domain steganography; According to the classification of steganography, it can be divided into text steganography, voice steganography, video steganography and binary steganography.