基于改进零树编码的图像联合压缩加密算法

Image Joint Compression-encryption Algorithm Based on Improved Zero-tree Coding

在认真研究算术编码和算术加密的基础上,提出了一种基于改进零树编码的图像联合压缩加密算法.使用密钥对图像压缩产生的原始上下文和原始判决进行修正,实现了图像联合加密.阐述了上下文修正和判决修正算法的规则,对其安全性进行分析.结合比特平面编码技术,可以使用不同密钥对不同小波分辨率的系数分别加密,实现分辨率选择性加密,以满足不同应用需求.对零树编码进行改进,加入自适应算术编码,并对联合压缩加密算法进行仿真.结果表明:相对原始图像压缩算法而言,所提出的图像联合压缩加密算法具有基本相当的压缩效率;相对区间分裂的联合加密算法而言,所提出算法具有更好的安全性.

On the basis of careful research on arithmetic coding and arithmetic encryption, a kind of image joint compression encryption algorithm based on improved zero-tree coding is proposed, where a key is used to modify the original context and the original decision produced in the process of image compression, and the image joint compression-encryption is realized in this way. In this work, the rule of the context modification and the decision modification algorithm is discussed and its security is analyzed. In order to meet different application requirements, different keys are used to encrypt separately the different wavelet resolution coefficients during bit-plane coding, so the resolution selective encryption is realized. Moreover, the Zero-tree coding was improved, and adaptive arithmetic coding is introduced to the improved Zero-tree coding, and then joint compression-encryption algorithm proposed is simulated. The simulation results show that the proposed image joint compression-encryption algorithm has the same compression efficiency compared with the original image compression algorithm; and the proposed algorithm has better security than the joint compression-encryption algorithm based on the interval splitting.