兰州大学机构库 >物理科学与技术学院
时滞系统中的自相似性和超混沌加密信息的破解
Alternative TitleSelf-similarity and recovering message masked by hyperchaotic signal of time-delay systems
张岩
Thesis Advisor汪映海
2004-05-28
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword时滞系统 半导体激光 自相似性
Abstract时滞系统是一类普遍存在又非常重要的非线性系统,本文对时滞半导体激光系统短延时区域的自相似性和时滞系统超混沌加密信息的破解进行了研究。 我们推广了时滞系统的Poincaré截面法,应用于时滞半导体激光系统,研究了Lang-Kobayashi模型在短延时区域的动力学性质,观察到系统中的自相似性现象。发现 Lang-Kobayashi模型的一系列外腔模均经历了稳定态-镜对称相似分岔-混沌的过程;一系列外腔模均对应一个LFF(low-frequency fluctuation)出现,并具有混沌-稳定态-LFF的特性,伴随着延时时间 变小,混沌、分岔、LFF消失,吸引子不再具有复杂结构;在短延时参数范围内,分岔现象消失,系统输出发生不连续现象,呈现出开关效应,对其可能的应用也作了简单讨论。 对于时滞系统超混沌加密信息的破解,我们提出了一种参数适应方法。在假设破解者掌握加密机制但没有获得加密密钥的前提下,使用该方法可准确获得加密密钥。进而对采用三种典型混沌加密机制(chaotic masking, chaotic modulation, chaotic switching)的时滞通信系统,分别进行了有效的破解。特别是,利用这种参数适应新方法,对具有Mackey-Glass时滞系统高维特性,又同时具有混沌跳转复杂性的加密通信系统,成功获取了加密信息。并且数值模拟结果表明,参数适应方法在噪声干扰和参数失调影响的情况下,具有良好的鲁棒性。
Other AbstractTime-delay systems are pervasive and important in nonlinear dynamics systems. In the thesis, the author investigates a single mode semiconductor laser with a short-time delayed feedback which present self-similarity, and recover message masked by hyperchaotic signal of a time-delay system. The Poincaré section technique for time-delay systems is developed. Using the method, we study the behavior of a single mode semiconductor modeled by Lang-Kobayashi equations in the short-time delay regime. Many self-similarities are found. As is increased, a series of external cavity modes (ECMS) exhibits the following route: stable state mirror-similar bifurcation chaos. At same time, each of ECMs is corresponded to a LFF (low-frequency fluctuation) regime. LFFs follow a similar route: chaos stable state LFF. With the continuous decrease of , we can no longer observe chaos, the mirror-similar bifurcation and LFFs, and there is no complex behavior in the attractors. In the short-time case, we found that output of the laser system may be regarded as a switch, and we discuss the regime of the switch, which can be used in some technological applications. We present a parameter adaptive method to recover message masked by hyperchaotic signal of a time-delay system. Using the method we obtain the security keys, based on the following assumptions: the eavesdropper knows the functional form of transmitter system, but does not know the secure parameters. Moreover, we recover the hidden message masked by three traditional encoded schemes of communications, i.e. the so-called chaotic masking, chaotic modulation and chaotic switching. The characteristic of the third scheme of communication is the switching between the chaotic attractors make the signal more complex. Particularly, we intercept the massage masked by hyperchaotic signal generated from a high-dimensional Mackey-Glass time-delay system for the third communication scheme by our method. In addition, we found numerically that the parameter adaptive method is robust to noise and parameter mismatching.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229361
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
张岩. 时滞系统中的自相似性和超混沌加密信息的破解[D]. 兰州. 兰州大学,2004.
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