改进的Fibonacci双置乱图像加密算法

Improved Image Encryption Algorithm Based on Double Scrambling of Fibonacci Transforms

图像置乱是实现图像加密的重要手段之一,其最终目的是改变图像像素的位置关系或者灰度值信息,改变图像的统计信息,从而达到图像加密的目的。为提升图像置乱效果和置乱性能,从均匀分块的角度出发,提出了一种改进的Fibonacci双置乱图像加密算法。首先采用均匀分块算法对原图像进行分块,使每个分块图像内的所有像素充分扩散到其他各个图像块中,以有效地削弱图像相邻像素的相关性;然后对每个图像块利用Fibonacci算法做像素位置置乱,以解除图像块的空间相关性;最后对整幅图像采用Fibonacci算法做像素值置乱,解除图像的色彩相关性。实验结果表明,该算法从本质上降低了图像内部相邻像素的相关性,有较强的抵御裁剪和常见噪声攻击的能力,利用双密钥提高了加密系统的安全性。

Image scrambling is one of the important means to realize image encryption and the ultimate purpose of scrambling is to change the pixel position or the gray value,change the statistic information of the image,so as to achieve the purpose of image encryption.To enhance the effect and performance of images scrambling,from the perspective of uniform blocking,a kind of improved double scrambling algorithm of Fibonacci transforms was put forward.At first,plain image was carried out,using uniform blocking algorithm,and each sub-block pixel was fully diffused to other sub-blocks in turn to weaken the image correlation between adjacent pixels effectively.Next,scrambling algorithm shuffled the pixels＇ position of each blocks to weaken the image spatial correlation by using Fibonacci.Finally,srambling algorithm shuffled the pixels＇ value of the whole image to weaken the iamge color correlation by using Fibonacci.The experimental results demonstrate that this algorithm can not only reduce the correlation of image adjacent pixels in essence but also has strong ability against shearing and common noise attacks in some degree,and it improves the encryption system＇s security by utilizing dual-key cipher.