基于整数变换的加密图像可逆信息隐藏算法

兼顾嵌入容量和算法安全性,提出了一种基于整数变换的加密图像可逆信息隐藏算法。内容所有者利用变换密钥,选取相应的两相邻像素为一组进行整数变换。变换后的像素组受该整数变换特性的约束,使得其中任意一个最低有效位(LSB Least Significant Bit)被替换后,仍能恢复出原始像素组。因此,信息隐藏者可根据相同的密钥找到加密图像中已进行变换的像素组,利用嵌入密钥替换对应像素的LSB完成隐秘信息可逆嵌入。只有同时拥有变换密钥和嵌入密钥,才能正确提取嵌入信息;只有同时拥有变换密钥及加密密钥,才能恢复出原图像,所以算法安全性较高。实验结果表明,该算法能够有效地在加密域中直接进行信息的嵌入及提取,并在解密后无损地恢复出原图像;而且该算法的嵌入率可高达0.47 bpp(bit per pixel)。

Reversible data hiding in encrypted image based on an integer transform

This paper proposed a novel reversible data hiding scheme in encrypted image which exploits an integer transform to achieve both high embedding capacity and security.In the proposed scheme, content owner implements an integer transform on the pixel groups which are selected by a transform key and composed of two adjacent pixels.Based on properties of the transform,the original pixels values can be recovered perfectly if one of LSBs(Least Significant Bit)in the transformed pixel group is altered.Data hider can seek the transformed pixel groups out from the encrypted image with the same transform key, select one pixel in each transformed group using an embedding key and embed additional data reversibly by replacing corresponding LSBs of the chosen pixels. Only if the receiver has both the transform key and embedding key, can the secret data be extracted without error.Only if the receiver has both the transform key and encryption key, can the original image be recovered perfectly. The experimental results demonstrate that additional data can be embedded and extracted directly in encrypted domain and the original image can be recovered losslessly. Besides, the embedding rate can reach 0.47 bpp(bit per pixel).