一种格式兼容的JPEG彩色图像自适应加密算法

JPEG Color Image Self-adaptive Encryption Algorithm with Format Compatibility

为了保障特殊格式图像的安全应用,需要针对其特点,深入研究与其格式兼容的图像加密算法。通过集成JPEG压缩标准与自适应加密思想,提出了具有格式兼容特性的JPEG彩色图像自适应加密算法。该算法分别选取JPEG压缩过程中的直流系数和按曲折排序的前16个交流系数构造出对应的系数矩阵。在自适应加密框架下,利用混沌产生随机密钥流,实现对系数矩阵和直流系数符号的加密,保证密文图像不会泄露明文色彩信息。仿真实验和分析证明,该算法加密效果良好,对压缩效果影响很小,且具有格式兼容性和足够的安全性。

To ensure the security application of images with special format,it is necessary to conduct an in-depth study of the corresponding image encryption algorithm compatible with its format. By integrating JPEG compression and the idea of self-adaptive encryption, a self-adaptive encryption algorithm for JPEG color image was proposed. DC coefficients and the first 16 AC coefficients in Zig-Zag order of JPEG compression are chosen to construct the corresponding matrices. Based on chaotic random sequence, self-adaptive encryption scheme is utilized to encrypt the coefficients, and the sign of DC coefficients is also encrypted to avoid color information leaking. Experimental results and analyses verify that both the security and performance of the proposed algorithm are good, and the impact on the compression is negligible. Furthermore, it is compatible with JPEG file format.