一种基于位平面分解的图像加密方法

Optical Image Encryption based on Bit Plane Division

为了找出速度快、保密性好的加密方法,研究了一种采用光电器件和位平面分解相结合的图像加密方法,将图像分解为位平面,利用伪随机矩阵作密钥,通过偏振编码对位平面分别加密。取lena图片进行加密、解密仿真实验,分析了该加密方法的安全性。结果表明,经加密、解密恢复的图像与原始图像一致,加密后,原始图像的像素灰度信息被淹埋,信息熵接近最大,不确定性极高,攻击者不易分析原图像的平均灰度值,降低泄漏特征信息的可能。

In order to find a quick and security encryption method, a new optical image encryption based on optoelectronic devices and bit plane division is studied. The image is divided into bit planes, the key bit stream was generated by random function, and bit planes are encrypted respectively by polarized coding method. In simulation calculation, ＂lena＂ picture is used for encryption, and security of the encryption is analyzed. The simulation results show that the recovered image from encrypted image is the same as original one. After encrypted, the information of gray-level of original image is concealed, and the information entropy of encrypted image is close to the biggest value. It is very hard for the attacker to find the gray-level value from encrypted image and recover the original image.