保守超混沌在数字图像加密中的应用

Application of Conservative Hyperchaos in Digital Image Encryption

基于保守超混沌信号,提出一种数字图像加密算法.该算法利用一个5维保守超混沌系统产生5通道时间序列对原图像分别进行RGB三基色像素级和比特级置乱,再对置乱的RGB三基色作异或操作.在此基础上,利用其中一个通道的时间序列作为密钥分别进行一次正向异或操作的扩散和S盒处理,一次反向异或操作的扩散与S盒处理及置乱,得到加密的图像.最后利用直方图、信息熵、密钥空间等安全性指标对该加密算法进行测试,并与一个五维耗散超混沌系统应用于图像加密的实例进行对比.数值结果表明保守混沌应用到数字图像加密的算法具有更高的安全性和可靠性.

We propose a digital image encryption algorithm based on conservative hyperchaotic signals.Based upon a 5-dimensional conservative hyperchaotic system,the algorithm generates a 5-channel time series to perform scrambling in both pixel-level and bit-level,and subsequently an XOR operation on scrambled RGB components of the original image.On this basis,an encrypted image is obtained with time series of one of the channels to perform a forward XOR operation and S-BOX processing,a reverse XOR operation,S-BOX processing,and scrambling.Finally,the encryption algorithm is evaluated with several security indicators such as histogram,information entropy,and key space.Performance of the encryption algorithm in digital image encryption is compared with that of a 5-dimensional dissipative hyperchaotic system.It shows that the algorithm based on conservative chaos has higher safety and reliability.