Research On Carrier-free Information Hiding Method For Covert Communicatio

The traditional information hiding technology often needs to modify the carrier,and the naturalness of the carrier is destroyed,which is easily detected by the steganalysis algorithm.In order to fundamentally solve this problem,the carrier-free information hiding technology came into being.This method transmits secret objects without modification and distortion,so it is difficult to distinguish from normal objects,so the carrier-free information hiding method has higher security.With the increasing demand for covert transmission of sensitive data such as military intelligence and medical information,coverless information hiding has become an important direction for researchers to explore new covert communication technologies.Therefore,it is of great practical value to study the coverless information hiding method for covert communication.However,in the traditional carrier-free covert communication method,the influence of the number and utilization of the carrier on the capacity is very critical.Sending a large number of unrelated carriers will further reduce the concealment of the channel.Therefore,how to design a carrier-free covert communication method with high capacity and strong concealment is a difficulty in research.At the same time,in order to solve the problem of the robustness of the carrier and the centralization of the channel,the blockchain can provide a safe and reliable environment for the transmission of sensitive information because of its decentralization and non-tampering characteristics.However,the information structure in the blockchain is fixed and open.Therefore,how to design a carrier-free covert communication method with high concealment is also a difficulty in research.The main research contents of this chapter are as follows:(1)A coverless information hiding method based on hash mapping and SIFT is studied.Use images of the same topic in large data sets and normalize the images.In order to solve the problem of data set utilization after image classification,covert communication will be divided into mapping and filtering processes.In the mapping stage,the hash algorithm is used to obtain the hash value order of the image,and the random sequence generated by the random algorithm is used to scramble the initial order.In the image filtering stage,the SIFT feature descriptor in the image wavelet domain is calculated,and the robustness of the algorithm is improved by optimizing the distribution of feature points.Finally,the low ratio matching and random sampling consistency algorithm are combined to solve the problem of similar image features of the same topic.Experimental results show that this method can improve the utilization of data sets,and further improve the robustness of image features compared with existing methods.(2)The blockchain covert communication method based on derived matrix is studied.Firstly,the initial private key is filled and the new private key is calculated by hash algorithm.Secondly,two types of blockchain addresses are generated by using double keys,and the address matrix is constructed by layering the addresses.The addresses of different layers map secret information interactively.Aiming at the concealment problem caused by fixed transaction characteristics,the address matrix is divided into square blocks with repeated areas,and the addresses in different blocks are scrambled to make the transaction characteristics of the address after multiple embeddings more match the transaction characteristics of the real address.The linear congruence method is used to generate uniform random numbers,which provides a random scrambling order for channel encryption and enhances the concealment and security of the channel.Experimental comparison and analysis show that the proposed method can effectively improve the concealment of the channel on the basis of ensuring the channel transmission efficiency.