利用可变预测的密文域可逆信息隐藏  

Reversible data hiding in encrypted images using variable prediction

作　　者：陈佳妮 徐达文[2] Chen Jiani;Xu Dawen(School of Mathematics and Big Data,Anhui University of Science and Technology,Huainan 232001,China;School of Cyber Science and Engineering,Ningbo University of Technology,Ningbo 315211,China)

机构地区：[1]安徽理工大学数学与大数据学院,淮南232001 [2]宁波工程学院网络空间安全学院,宁波315211

出　　处：《中国图象图形学报》2024年第1期95-110,共16页Journal of Image and Graphics

基　　金：国家自然科学基金项目(62071267);浙江省自然科学基金项目(LR20F020001);宁波市自然科学基金项目(2023J022)。

摘　　要：目的随着云计算和云存储场景中用户隐私保护的需求日益增加,密文域图像可逆信息隐藏(reversible data hiding in encrytpted images,RDHEI)受到了广泛关注。然而大多数RDHEI算法以提升嵌入率和保障图像加密安全性为目的,复杂化图像的预处理操作。为此,提出一种基于可变预测和多MSB(most significant bit)替换的密文域图像可逆信息隐藏算法。方法提出可变预测位平面翻转策略,用相邻像素值迭代预测当前像素值的多位最高有效位。若预测值比翻转值更接近目标像素值,则当前预测位平面可以用于信息隐藏,将其比特值修改为0。同时,用位置图自适应地标记可嵌入像素点。所生成的位置图具有稀疏特征,可以使用算术编码无损压缩。最后,对预留空间后的图像进行加密,通过多MSB替换的策略嵌入隐秘信息和压缩位置图。结果经实验测试,本文算法在BOWS-2(break our watermarking system 2nd)数据集上平均嵌入率为2.953 bit/像素,并记录了1000幅图像在预处理前后的每个位平面信息熵,其中最高位平面的信息熵比原始MSB下降了0.76,说明可变预测位平面翻转将多个高位平面翻转为0,使其处于稀疏状态,有效增加了嵌入空间。结论本文算法利用明文图像的空间相关性,对高位平面进行翻转与替换,从而为隐秘信息预留了更多的嵌入空间。所提方法可无损恢复原始图像,且无差错提取隐秘信息。Objective With the growing demand of users for privacy protection in cloud computing and cloud storage scenarios,reversible data hiding in encrypted images(RDHEI)has gained widespread attention.RDHEI has three independent roles,namely,image holder,service provider,and image receiver.Before uploading the images to the cloud,the holder encrypts it,and the service provider embeds some necessary information into the encrypted image for management and other purposes in the cloud server.After obtaining the marked encrypted image,the receiver can opt to extract the embedded data or recover the image according to its own secret key.The existing RDHEI schemes can be divided into two categories:vacating room after encryption(VRAE)and reserving room after encryption(RRBE).The largest difference between two types of methods lies in the different processes before and after the encryption phase.For RRBE,before uploading the encrypted image to the service provider,essential preprocessing needs to be operated by the image holder for reserving the data space.For VRAE,the image holder can upload the encrypted image directly,and the service provider conducts the data space for the preparation of the subsequent embedding.The operation of vacating room in two types of methods is a redundant processing of images.The core is to select the point to use pixel correlation,and it is also a compromise between embedded capacity and transmission security.However,most RDHEI algorithms complicate the preprocessing of images to improve the embedding rate and ensure the security of image encryption.This paper proposes a reversible data hiding algorithm based on variable prediction and multi-most significant bit(MSB)replacement in encrypted images.Method The proposed algorithm mainly consists of the following parts:image preprocessing,exclusive encryption,data embedding,data extraction,and image recovery.This paper proposes a variable prediction bit-plane inversion(VPBI)strategy,which aims to make full use of the whole relevance of the image.First

关 键 词：可逆信息隐藏 图像加密 可变预测 多MSB替换 自适应位置图 

分 类 号：TP309[自动化与计算机技术—计算机系统结构]