共查询到20条相似文献,搜索用时 15 毫秒
1.
《Physics letters. A》1999,251(3):169-176
We present a new chaotic masking scheme by using synchronized chaotic systems. In this method, synchronization and message transmission phases are separated, and while synchronization is achieved in the synchronization phases, the message is only sent in message transmission phases. We show that if synchronization is achieved exponentially fast, then under certain conditions any message of any length could be transmitted and successfully recovered provided that the synchronization length is sufficiently long. We also show that the proposed scheme is robust with respect to noise and parameter mismatch under some mild conditions. 相似文献
2.
The design of an efficient one-way hash function with good performance is a hot spot in modern cryptography researches. In this paper, a hash function construction method based on cell neural network with hyper-chaos characteristics is proposed. First, the chaos sequence is gotten by iterating cellular neural network with Runge Kutta algorithm, and then the chaos sequence is iterated with the message. The hash code is obtained through the corre- sponding transform of the latter chaos sequence. Simulation and analysis demonstrate that the new method has the merit of convenience, high sensitivity to initial values, good hash performance, especially the strong stability. 相似文献
3.
SC混沌比例投影同步方法在保密通信中的应用 总被引:1,自引:0,他引:1
利用基于线性稳定性准则的SC混沌比例投影同步方法,提出一种应用于保密通信的混沌掩盖方案.适当分离出混沌系统的线性项与非线性项,构造一个非线性驱动向量函数,混沌状态变量包含用于投影同步的比例因子,把所需传递的有用信息掩盖入其中一个分量上,得到混沌载波信号,提高加密信息的复杂度和解码的困难度.以Lorenz吸引子和超混沌Rössler吸引子为例进行数值仿真,详细分析传输的正弦信息加密解密全过程,给出简单、最优的混沌掩盖方案,数值分析证明比例投影同步方法应用于保密通信领域的有效性. 相似文献
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提出了一种基于强跟踪滤波器的混沌保密通信方法. 在发送端, 混沌映射和信息符号被建模成非线性状态空间模型, 信息符号被加性混沌掩盖或乘性混沌掩盖调制, 然后通过信道输出. 在接收端, 驱动信号被接收, 使用带有贝叶斯分类器(信息符号估计)的强跟踪滤波器算法动态地恢复信息符号. Logistic混沌映射的仿真表明, 当信息符号为二进制编码时, 不管是加性混沌掩盖调制还是乘性混沌掩盖调制, 强跟踪滤波器均能较好地从混沌信号中恢复信息符号. 与扩展卡尔曼滤波器相比, 由于卡尔曼滤波器对于离散的信息符号跟踪能力差, 混沌映射中信息符号难以恢复, 比特误码率高. 因此, 这种基于强跟踪滤波器的混沌保密通信方法是有效的. 相似文献
6.
Control of chaos via an unstable delayed feedback controller 总被引:7,自引:0,他引:7
Pyragas K 《Physical review letters》2001,86(11):2265-2268
Delayed feedback control of chaos is well known as an effective method for stabilizing unstable periodic orbits embedded in chaotic attractors. However, it had been shown that the method works only for a certain class of periodic orbits characterized by a finite torsion. Modification based on an unstable delayed feedback controller is proposed in order to overcome this topological limitation. An efficiency of the modified scheme is demonstrated for an unstable fixed point of a simple dynamic model as well as for an unstable periodic orbit of the Lorenz system. 相似文献
7.
This Letter proposes two different attacks on a recently proposed image based on hyper-chaos. The cryptosystem under study proceed first by shuffling the image rows and columns to disturb the high correlation among pixels by iterating the logistic map. Second, a keystream is generated to mix it with the pixels of the shuffled image using hyper-chaos. These two processes in the encryption stage present weakness, and a chosen plaintext attack and a chosen ciphertext attack can be done to recover the ciphered-image without any knowledge of the key value. It just demands three couples of plaintext/ciphertext to break totally the cryptosystem. 相似文献
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9.
In this work, a novel combination synchronization scheme in which synchronization of a new combination hyperchaotic drive system formed by combining state variables of the original drive system with appropriate scaling factors with a response hyperchaotic system is considered. A self-combination system is constructed from hyperchaotic Lorenz system by combining state variables of the Lorenz system with appropriate scaling factors. Modified function projective synchronization between the newly constructed combination hyperchaotic Lorenz system and hyperchaotic Lu system is investigated using adaptive method. By Lyapunov stability theory, the adaptive control law and the parameter update law are derived to make the state of two systems as modified function projective synchronized. Numerical simulations are done to show the validity and effectiveness of the proposed synchronization scheme. 相似文献
10.
提出了一种新型的混沌系统同步方法,即错位投影同步,要求驱动系统和响应系统中的所有状态向量,至少有一对不是按照原有的对应关系成比例同步,而是按照向量的错位关系成比例投影同步.以新型的四维超混沌Qi系统为例,分析出23种混沌系统的同步方案.针对其中一种同步,基于Lyapunov稳定性理论,设计有效的非线性控制器,实现初始值不同的两个超混沌Qi系统错位投影同步.另外,将该方法应用于混沌保密通信中,基于改进的混沌掩盖通信原理,在发送端使用超混沌信号对信息信号进行加密并发送,最后从同步后的接收端系统不失真地恢复出有用信号.数值仿真表明,该方案有着良好的通信和保密特性. 相似文献
11.
In this paper, a new numerical simulation approach is proposed for the
study of open-loop frequency response of a chaotic masking system. Using
Chua's circuit and the Lorenz system as illustrative examples, we have shown
that one can employ chaos synchronization to separate the feedback network
from a chaotic masking system, and then use numerical simulation to obtain
the open-loop synchronization response, the phase response, and the
amplitude response of a chaotic masking system. Based on the analysis of the
frequency response, we have also proved that changing the amplitude of the
exciting (input) signal within normal working domain does not influence the
frequency response of the chaotic masking system. The new numerical
simulation method developed in this paper can be extended to consider the
open-loop frequency response of other systems described by differential or
difference equations. 相似文献
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A simple method to simultaneously achieve synchronization andanti-synchronization in chaotic systems 下载免费PDF全文
In this paper, a novel adaptive control approach is
presented to simultaneously achieve synchronization and
anti-synchronization in partially linear chaotic systems. Through
appropriately separating state vectors of such systems,
synchronization and anti-synchronization could be simultaneously
realized in different subspaces, which may be strictly proven
theoretically. Simulation results for a Lorenz chaotic system and a
new hyper-chaotic system are provided to illustrate the
effectiveness of the proposed method. Finally, a new secure
communication scheme based on such a synchronization phenomenon of
the hyper-chaotic system is demonstrated. Numerical results show
success in transmitting a periodic signal with high security. 相似文献
14.
对Pecora和Carroll的混沌自同步方案的延迟同步误差进行了研究.在计算机上对Lorenz混沌系统伪装的延迟同步误差进行了模拟:给定系统参数,对应不同延迟时间,得出了均方误差与采样步长的关系曲线;给定系统参数和延迟时间,对应不同采样步长,得到了混沌时间序列的误差曲线;给定采样步长,对应不同的系统参数,获得了混沌时间序列的尺度效应和均方误差与采样步长的关系曲线.提出了减小延迟同步误差的一些方法,得到一些对混沌同步和混沌控制应用有意义的结果.
关键词:
混沌同步
时间同步
误差分析 相似文献
15.
Circuit implementation and multiform intermittency in ahyper-chaotic model extended from Lorenz system 下载免费PDF全文
<正>This paper presents a non-autonomous hyper-chaotic system,which is formed by adding a periodic driving signal to a four-dimensional chaotic model extended from the Lorenz system.The resulting non-autonomous hyper-chaotic system can display any dynamic behaviour among the periodic orbits,intermittency,chaos and hyper-chaos by controlling the frequency of the periodic signal.The phenomenon has been well demonstrated by numerical simulations,bifurcation analysis and electronic circuit realization.Moreover,the system is concrete evidence for the presence of Pomeau-Manneville Type-Ⅰintermittency and crisis-induced intermittency.The emergence of a different type of intermittency is similarly subjected to the frequency of periodic forcing.By statistical analysis,power scaling laws consisting in different intermittency are obtained for the lifetime in the laminar state between burst states. 相似文献
16.
A new image encryption algorithm based on the fractional-order hyperchaotic Lorenz system 总被引:3,自引:0,他引:3 下载免费PDF全文
We propose a new image encryption algorithm on the basis of the fractional-order hyperchaotic Lorenz system. While in the process of generating a key stream, the system parameters and the derivative order are embedded in the proposed algorithm to enhance the security. Such an algorithm is detailed in terms of security analyses, including correlation analysis, information entropy analysis, run statistic analysis, mean-variance gray value analysis, and key sensitivity analysis. The experimental results demonstrate that the proposed image encryption scheme has the advantages of large key space and high security for practical image encryption. 相似文献
17.
We propose a new image encryption algorithm on a basis of the fractional-order hyperchaotic Lorenz system. While in the process of generating a key stream, the system parameters and the derivative order are embedded in the proposed algorithm to enhance the security. Such an algorithm is detailed in terms of security analyses, including correlation analysis, information entropy analysis, run statistic analysis, mean-variance gray value analysis, and key sensitivity analysis. The experimental results demonstrate that the proposed image encryption scheme has the advantages of large key space and high security for practical image encryption. 相似文献
18.
Ching-Sheng Hsu 《Optics Communications》2010,283(9):1737-108
In recent years, digital watermarking technology has been widely used for property rights protection and integrity authentication of digital images. Image integrity authentication is usually done by a fragile watermarking scheme. When authenticating image integrity, one must extract the embedded authentication message from the image for comparison with the image feature to identify whether the image has been tampered with, and if so, locate the affected area. However, such authentication schemes may result in detection error problems. Namely, the tampered area may be misjudged as not having been tampered with, or vice versa. Hence, methods that effectively reduce errors in tampering detection have become an important research topic. This study aims to integrate a probability theory to improve image tampering detection accuracy and precision. The scheme includes two processes: the embedding of an image authentication message and tampering detection. In the image tampering detection process, in addition to identifying whether the image has been tampered with and locating the tampered area, through the authentication message embedded in the image, a probability theory is employed to improve previously obtained detection results to enhance authentication accuracy. The experimental results reveal that the proposed scheme performs well in terms of detection precision and authentication accuracy rate. 相似文献
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