Reversible Data Hiding Algorithms For Encrypted Images Based On Pixel Prediction Technologies

Currently,people use the Internet to transmit information more and more frequently,and multimedia data such as images and videos are widely used in various Internet applications.Therefore,how to ensure the safety of information in the transmission process has become an important issue to be solved urgently.In the initial stage,researchers used encryption technology to scramble the original information content into messy code with no practical meaning,which effectively solved the problem of information security.With the rise of cloud storage and big data technologies,more and more people want to transfer data to the cloud for storage.Due to distrust of service providers,many users encrypt information before uploading it to the cloud,which leads to a large amount of encrypted data in th cloud.For cloud applications,more and more researchers are studying reversible data hiding technology for encrypted images,hoping to embed information in ciphertext images for transmission,so as to ensure the security of embedded data and better protect the carrier image.This paper uses encrypted image as a carrier,and use technologies such as adaptive prediction error coding,most significant bit prediction,fixed-length coding and lossless compression to design reversible data hiding algorithms based on encrypted images.The main research results are summarized as follows.(1)A reversible data hiding algorithm for encrypted images based on adaptive prediction error coding is proposedThe main work of this research is to propose an adaptive predictive error coding scheme,and use this scheme,to design a reversible data hiding algorithm for encrypted images based on adaptive predictive error coding.The algorithm first preserves the spatial correlation of the original image in the encryption domain through a block-based encryption scheme,and uses adaptive prediction error coding technology to vacate room for data embedding.Then,the prediction error is adaptively coded according to the block content,effectively freeing up space from the ciphertext image block,so as to realize the secret data embedding.When extracting the data and recovering the image,the secret data is extracted in image blocks,and then the recovery of the image is completed using the auxiliary information.The experimental results show that the algorithm outperforms many reversible data hiding algorithms of the same type in terms of embedding capacity and running time.(2)A reversible data hiding algorithm for encrypted images based on prediction error and fixed-length coding technology is proposedThe main work of this research is to design a method to predict the prediction error of the current pixel by using the weighted sum of adjacent pixels,and use this scheme to design a reversible data hiding algorithm for encrypted images based on prediction error and fixed-length coding technology.The algorithm first uses this prediction error scheme to preserve the spatial correlation of the whole image to free up the embedding space before image encryption,then the original image is encrypted and chunked,followed by marking the pixel blocks separately using fixed-length coding technique.Finally,the secret data is embedded in the ciphertext image according to the markings of the pixel blocks.When extracting the data and recovering the image,the secret data is extracted in image blocks and then the image is recovered by auxiliary information.The experimental results show that the embedding rate of this algorithm is greater than that of a variety of literature algorithms,and it has better performance in terms of embedding capacity.(3)A reversible data hiding algorithm for encrypted images based on the most significant bit prediction is proposedThe main work of this research is to design a scheme to predict the most significant bit of the pixel,and use this scheme to design a reversible data hiding algorithm for encrypted images based on the most significant bit prediction.The algorithm first uses this prediction scheme to predict multiple most significant bits of each pixel,and after the prediction is completed,the image is chunked and all the correctly predicted pixel blocks are freed up for embedding data and recording the position.The image is then encrypted,followed by losslessly compressing the location map and embedding the image using run length coding techniques.The data hider can embed the secret data into the ciphertext image based on the location map.In extracting the data and recovering the image,the location map information is extracted first,followed by extracting the secret data based on the location map,and finally the image is recovered using the auxiliary information.The experimental results show that the algorithm is superior to four same types of literature algorithms in terms of embedding capacity.