Image encryption using high-dimension chaotic system

In recent years, the chaos based cryptographic algorithms have suggested some new and efficient ways to develop secure image encryption techniques. This paper proposes a new approach for image encryption based on a high-dimensional chaotic map. The new scheme employs the Cat map to shuffle the positions, then to confuse the relationship between the cipher-image and the plain-image using the high-dimensional Lorenz chaotic map preprocessed. The results of experimental, statistical analysis and key space analysis show that the proposed image encryption scheme provides an efficient and secure way for real-time image encryption and transmission.     

基于Arnold置乱和DCT变换的图像水印算法

采用灰度图像为水印信息,对基本离散余弦变换域图像数字水印算法进行改进,为保证信息的安全性,在嵌入宿主图像之前结合Arnold变换进行加密。通过在图像块离散余弦变换域中修改中频区来嵌入不同强度的水印。实验结果证明该算法提高了水印检测的准确性,并且该算法具有较好的不可见性和鲁棒性。     

基于改进Henon映射和超混沌的双重语音加密算法

针对现有语音混沌加密算法密钥空间小、安全性差、加密效率低且无法实现密钥复杂度与加密效率的权衡等问题,提出了一种改进Henon映射和超混沌的双重语音加密算法。首先,为了使Henon映射具有更大的混沌空间和更高的混沌复杂度,通过扩展控制参数范围将非线性三角函数作为输入参数变量等手段对经典Henon映射进行了改进;其次,利用改进的Henon映射生成伪随机序列,并对语音数据进行单次不重复置乱加密,获得语音数据的初次加密结果;最后,利用Lorenz超混沌系统对初次加密后的语音数据进行Arnold二次置乱加密和异或扩散加密,获得最终的密文语音数据。实验结果表明,与现有方法相比该算法具有更大的密钥空间和更高的加密效率,且对各种密码攻击拥有更好的鲁棒性。     

Alternate Phase Synchronization in Coupled Chaotic Oscillators

Phase locking dynamics in coupled chaotic oscillators is investigated.For chaotic systems with a poorly coherent phase variable,the imperfect phase locking can be observed befor the onset of a complete phase synchronization.The temporal alternations among n:n phase lockings are found,which originate from an overlap of m:n Arnold tongues.     

长曲线上的手术和基本不变量

本文给出长曲线上进行插入和推进时的基本不变量的变化公式及其应用．     

ARNOLD CIRCULATION AND MULTI-OPTIMAL DYNAMIC CONTROLLING MECHANISMS IN DRAGONFLY WINGS

This paper aims to reveal the multi-optimal mechanisms for dynamic control in dragonfly wings. By combining the Arnold circulation with such micro/nano structures as the hollow inside constructions of the pterostigma, veins and spikes, dragonfly wings can create variable mass, variable rotating inertia and variable natural frequency. This marvelous ability enables dragonflies to overcome the contradictory requirements of both light-weight-wing and heavy-weight-wing, and displays the multi-optimal mechanisms for the excellent flying ability and dynamic control capacity of dragonflies. These results provide new perspectives for understanding the wings' functions and new inspirations for bionic manufactures.     

Covering relations for multidimensional dynamical systems—II

We use a topological technique based on covering relations to prove the existence of chaotic orbits for certain Hamiltonian systems with several degrees of freedom. This paper relies on an earlier work of Zgliczyński and Gidea.     

The Arnold conjecture for a product of monotone manifolds and Calabi-Yau manifolds

We prove the Arnold conjecture for a product of finitely many monotone symplectic manifolds and Calabi-Yau manifolds. The key point of our proof is realized by suitably choosing perturbations of the almost complex structures and Hamiltonian functions for the product case. Supported by the National Natural Science Foundation of China     

基于logistic混沌序列的改进算法及其性能分析

针对目前混沌系统数字化后受硬件有限精度的影响,使得数字混沌0/1序列最终都将变成类短周期序列,降低了混沌加密系统的安全性。为克服此缺点本文将logistic混沌序列与Arnold变换相结合,提出了一种新型的logistic混沌序列算法,并通过实验对该算法产生的二值序列的自相关性、随机性等性能做了对比分析。同时利用此改进算法对数字图像进行加解密,结果表明新型的logistic混沌序列算法具有良好的安全性,能够满足保密通信的需要。     

基于内容自适应的实时视频水印算法研究

设计了一种基于内容自适应的实时视频水印算法。该算法使用Arnold变换对原始水印图像进行置乱,能够基于视频内容自适应地将水印图像嵌入到原始视频的每一帧中,且实现了水印图像的盲提取。实验结果表明,该算法具有实时性、不可感知性,对高斯噪声、Speckle及帧裁剪等常规攻击具有较好的稳健性,可以作为一种防插播、防篡改技术应用于数字广播电视领域中。