基于一维混沌映射的高效图像加密算法

随着多媒体技术的发展,基于数字图像的应用日益普及,图像本身的安全问题及图像所有者的隐私问题愈发严重。不同于文本数据,数字图像作为一种二维数据,其数据量大,冗余度高,像素间相关性强,将传统的一维数据加密方法直接应用于图像加密中难以达到加密的效果。当前,基于混沌理论的加密方法是图像加密领域的主流方法之一,其往往采用置乱-扩散的经典结构,利用所生成混沌序列的高随机性保证加密结果的安全性,同时具备较高的加密效率。然而,为了进一步增强加密算法的安全性,此类方法提出了大量复杂的混沌映射,如超混沌、多级混沌等,但它们的计算复杂度较一维混沌映射有了大幅增加。对此,文中设计了一种高效的一维复合混沌映射SPM,其将Sine映射和PWLCM映射结合,扩大了混沌映射的范围并保证了结果的遍历性,在不降低安全性的前提下极大地提升了混沌序列的生成效率;基于此,提出了一种新型结构下的高效图像加密算法,该算法仅需一轮置乱-扩散-置乱过程即可完成图像的加密,相较于传统方法减少了加密的轮数,进一步提升了加密的效率。实验表明,所提方法能够有效抵御选择明文/密文攻击,相较于已有算法,加密效率平均提升了约58%,具备较强的实用性。

Efficient Image Encryption Algorithm Based on 1D Chaotic Map

With the development of multimedia technologies,the applications based on digital images have become more and more popular,the security issues of the image itself and the privacy problems of the image owners are more severe in current environment.Different from text,digital images data as a two-dimensional data with large volume of data,high redundancy and strong correlation between pixels.It is difficult to achieve the effect of encryption when traditional encryption method is applied directly to image encryption.At present,encryption based on chaos theory is one of the mainstream methods in the field of image encryption,which using the classical structure of scrambling-diffusion,making use of the high randomness of the chao-tic sequences to ensure the security of the encryption results,and has a high encryption efficiency at the same time.In order to further improve the security of chaotic encryption algorithms,a large number of complex chaotic maps,such as hyper-chaos and multi-level chaos,have been proposed,however,the computational complexity is much higher than that of one-dimensional chaotic maps.To solve this problem,an efficient chaotic map called SPM is designed through combining Sine map and PWLCM,which expands the chao-tic range,enhances the ergodicity and lifts up the generation speed of chaotic sequence without reducing security.Based on this,an image encryption algorithm based on a novel structure is designed.Only one round of scrambling-diffusion-scrambling is needed to complete the encryption in this method,which reduces the encryption rounds compared to traditional methods and further improves the efficiency of encryption.The fully experiments show that the proposed method can effectively resist the chosen plain-image/cipher-image attacks and the encryption efficiency is improved by about 58%on average,meaning a high practicability.