基于图像块分组的加密域可逆信息隐藏

摘要

In order to achieve better performance, a reversible data hiding scheme for encrypted image was proposed based on image block grouping. Using this scheme, the original image of the content owner was encrypted by exploiting a stream cipher. When obtaining an encrypted image by the content owner, the encrypted image was divided into non-overlapping blocks by the data-hider, and the image blocks were grouped by the data hiding key. Subsequently, additional data was embedded into the encrypted image by modifying one of the image blocks in each group. With an encrypted image containing additional data, the receiver can readily gain decrypted version similar to the original image using the encryption key. Meanwhile, with the aid of spatial correlation in natural image, he or she can perfectly recover the original image and correctly extract additional data by comparing the smoothness of image blocks in each group . Experimented result shows that the proposed scheme can acquire a higher payload with good image quality. Furthermore, this scheme is suitable for practical application due to its simple operation and easy realization.%为了提升加密域可逆信息隐藏的方法性能，提出了一种基于图像块分组的加密域可逆信息隐藏方案。在该方案中，内容所有者采用流密码异或加密图像，随后数据隐藏者将加密的图像进行分块，并按一定比例将图像块分组，再根据待嵌入的信息修改每组中相应的图像块，从而实现信息嵌入。对于含有秘密信息的加密图像，接收者可使用加密密钥解密得到与原始图像近似的解密图像，然后根据自然图像空间相关性，通过比较每组中各图像块的平滑度找出被修改的图像块，从而实现秘密信息正确提取和图像完美恢复。实验证明本方法在保证一定图像质量的情况下有较大的信息嵌入量。