基于四元数离散余弦变换和相移数字全息干涉的彩色图像加密技术

Color Image Encryption Scheme Based on Quaternion Discrete Cosine Transform and Phase-shifting Interferometry

结合四元数离散余弦变换(QDCT)、Henon映射和两步相移数字全息干涉术,提出一种彩色图像加密新方法.所提加密技术首先应用QDCT对彩色图像进行整体式的处理,然后使用Fibonacci变换和基于分数傅里叶变换的双随机编码技术进行加密,并采用两步相移数字全息干涉术记录加密结果.为避免传输随机相位掩模(RPM)给解密方引起的安全风险,利用Henon映射生成双随机编码过程所需的RPMs加以解决.实验表明所提加密系统具有高安全性和对选择明文等攻击具有鲁棒性.

A color image encryption scheme based on the quaternion discrete cosine transform(QDCT), the Henon map and two-step phase-shifting interferometry(PSI)is presented. In the proposed method,the original color image is processed holistically in a vector manner using QDCT first,then the components of the QDCT-transformed original image are encoded by use of the Fibonacci transform and the fractional Fourier transform-based double random phase encoding(DRPE)technique. The resulting encrypted signal is recorded as two real-valued interferograms by employing two-step PSI. To avoid the security risks caused by sending the whole random phase masks(RPM)to the receiver side for decryption,the two RPMs used in DRPE is generat-ed by utilizing Henon map. Experiments show that the proposed scheme has high security level and certain ro-bustness against some attacks such as chosen plaintext attack.