Abstract:

In order to improve the security of image encryption and increase the information hiding capacity of encrypted images， a reversible information hiding algorithm based on pixel prediction and secret image sharing was proposed. Firstly， the shared matrix was used to process an image line-by-line and save it into four shared images. Secondly， random key-encrypted shared images were generated using a 2D chaotic mapping. Thirdly， the Median Edge Detector （MED） was used to predict the pixel value of the embedded position in the shared image. The predicted value was aligned to the same bits as the original pixel from the high bit， and the label value was recorded according to the rule. The high three bits of the reference pixel were stored into the embeddable bits. Finally， the label value was stored in the high bits of the reference pixel， and the remaining embeddable bits were the embedding capacity of the proposed algorithm. Experimental results show that the proposed algorithm can provide large capacity embedding space for information hiding， realize the reversible data hiding and the lossless recovery of encrypted images according to the （k，n） threshold strategy.

Key words: image encryption, shared matrix, reversible data hiding, Median Edge Detector (MED), embedded space

摘要：

为增强图像加密的安全性以及增加加密图像的信息隐藏容量，提出一种基于像素预测和秘密图像共享的可逆信息隐藏算法。首先，利用共享矩阵逐行处理图像并分存为四个共享图像；其次，利用二维混沌映射生成随机密钥加密共享图像；再次，利用中值边缘检测器（MED）预测共享图像中可嵌入位置的像素值，预测值与原像素从高位开始比对相同的位数，根据规则记录标签值，提取参考像素的高三位与认证信息存入可嵌入位；最后，将标签值存入参考像素高位，剩余的可嵌入位为所提算法的嵌入容量。实验结果表明，所提算法不仅能够为信息隐藏提供大容量的嵌入空间，而且能够实现可逆数据隐藏并根据（k，n）阈值策略实现加密图像的无损复原。

关键词: 图像加密, 共享矩阵, 可逆数据隐藏, 中值边缘检测器, 嵌入空间