一种基于外部密钥的混沌加密方法  

A New Chaotic Cryptosystem by Using External Key

作　　者：张欣[1] 杨德刚[1] 朱凯[1] 

机构地区：[1]重庆师范大学信息科学与工程学院,重庆400047

出　　处：《重庆师范大学学报（自然科学版）》2010年第2期57-60,64,共5页Journal of Chongqing Normal University:Natural Science

基　　金：国家自然科学基金(No.10971240);重庆市科委自然科学基金(No.CSTC2008BB2366;No.CSTC2008BB2364);重庆市教委科技计划(No.KJ090803;No.KJ080805;No.KJ080806;No.KJ080817)

摘　　要：提出了一种基于斜帐篷映射的混沌加密方法。分析了斜帐篷映射的数学性质,该混沌系统生成的混沌序列具有良好的统计特性。该方法采用128位二进制数代替系统参数作为密钥,混沌映射所需的所有参数都由外部密钥计算产生,通过随机改变混沌的迭代次数、分段的频率以及改变混沌的初始值和参数,提高混沌序列的复杂度,增加了混沌系统的安全性。同时引入扩散机制,当明文仅出现微小的变动时,使得对应的密文与变动之前的密文完全不同,增加了密文分析的难度。仿真实验和理论分析都证明该算法具有较高的效率和安全性,能够有效抵抗统计攻击和已知明文攻击。In this paper, a new chaotic cryptosystem based on skew-tent map is proposed. The mathematic characteristics of this map prove that the chaotic sequence generated from it has good statistical property. This method uses 128-bit binary sequence as key instead of system parameters. All the system parameters required by this chaotic map are calculated by external key. By changing iterating number times, piecewise frequency, chaotic initial conditions and parameters randomly, the chaotic sequence is much more complex and the security of this eryptosystem has improved greatly. At the same time, diffusion mechanism has been introduced in the algorithm. This means that every bit change in the plain image can influence multi-bit in the cipher image. This method ensures that cipher image pixel can change largely and be very different from former cipher image that plain image hasnt been changed when plain image pixel changes slightly, and increases the difficulty of cipher analysis. It has been proved by many simulated experiments and theoretical analysis that this algorithm owns higher efficiency and security and can resist the statistcal and known-plaintext attacks.

关 键 词：LOGISTIC映射 斜帐篷映射 混沌加密 外部密钥 

分 类 号：TP309[自动化与计算机技术—计算机系统结构]