Chong Fu

An Improved Image Encryption Algorithm Based on Chaotic Maps

This paper proposes a 3-D Lorenz system based image encryption scheme, which improves the security and performance of the encryption system over conventional one dimension chaos based ones. The balance and correlation properties of the analog sequences generated by Lorenz system are analyzed and a pre-process method is proposed, which makes the key stream have good statistical properties. Three initial parameters of Lorenz system are combined together as one key, which greatly enlarges the key space under precision restricted condition. The encryption speed is also improved since the position permutation and grayscale substitution of a pixel can be done by one iteration operation. Besides, the encryption system is strong against adaptive parameter synchronous attack since it has more complicated structure than one dimension ones. The experimental results indicate that the algorithm is more secure and efficient than conventional ones.

An Image Encryption Scheme Based on Lorenz Chaos System

This paper proposes a 3-D Lorenz system based image encryption scheme, which improves the security and performance of the encryption system over conventional simple chaos system based ones. The balance and correlation properties of the analog sequences generated by Lorenz system are analyzed and a pre-process method is proposed, which makes the key stream have good statistical properties. Three initial parameters of Lorenz system are combined together as one key, which greatly enlarges the key space under precision restricted condition. The encryption speed is also improved since the position permutation and grayscale substitution of a pixel can be done by one iteration operation. Besides, the encryption system is strong against adaptive parameter synchronous attack since it has more complicated structure than simple chaos system based ones. The experimental results indicate that the algorithm is more secure and efficient than conventional algorithms.

An Improved Chaos-Based Image Encryption Scheme

Chaos theory provides a new approach to image encryption technology. The key stream generator is the key design issue of an image encryption system, it directly determines the security and efficiency of the system. This paper proposes an improved chaos-based key stream generator to enlarge the key space, extend the period and improve the linear complexity of the key stream under precision restricted condition so as to enhance the security of a chaos-based image encryption system. The generator is constructed by three Logistic maps and a nonlinear transform. The balance and correlation properties of the generated sequence are analyzed. The sequence is proved to be a binary Bernoulli stochastic sequence and the distribution of the differences between the amounts of 0 and 1 is analyzed. The side lobes of auto and cross correlation are proved to obey normal distribution N(0, 1/N). The experimental results indicate that the scheme has advantages of long period and strong anti various attack ability over conventional chaos-based encryption system.

A fast pseudo stochastic sequence quantification algorithm based on chebyshev map and its application in data encryption

Chaos theory has been widely used in cryptography fields in recent years and the performance of the pseudo stochastic sequence quantified from chaos map has great influence on the efficiency and security of an encryption system. In this paper, an improved stochastic middle multi-bits quantification algorithm based on Chebyshev map is proposed to enhance the ability of anti reconstruction a chaos system through reverse iteration and improve the performance of the generated sequence under precision restricted condition. The balance and correlation properties of the generated sequence are analyzed. The sequence is proved to be a binary Bernoulli sequence and the distribution of the differences between the amounts of 0 and 1 is analyzed. The side lobes of auto correlation and values of cross correlation are proved to obey normal distribution N (0, 1/N).

The design and implementation of a general reduced TCP/IP protocol stack for embedded Web server

The embedded Web server technology is the combination of embedded device and Internet technology, which provides a flexible remote device monitoring and management function based on Internet browser and it has become an advanced development trend of embedded technology. In this paper, a design and implementation scheme of a general reduced Web server protocol stack which aims at the limited resources characteristic that the embedded system has was proposed based on AT90S8515 single chip that uses RISC technology and RTL-8019 network interface controller hardware platform. The overall design issue was thoroughly discussed and the implementation methods of core protocols in protocol stack such as 802.3, ARP, IP, TCP and HTTP were analyzed in detail

An Improved Chaos-Based Stream Cipher Algorithm

This paper proposes an improved chaos-based stream cipher algorithm to enhance the security of an encryption system under precision limited condition. The key stream generator is constructed by three one dimension chaotic maps and their nonlinear transform. The balance and correlation properties of the key stream are analyzed. The sequence is proved to be a binary Bernoulli sequence and the distribution of the differences between the amounts of 0 and 1 is analyzed. The side lobes of auto and cross correlation are proved to obey normal distribution N(0, 1/N). Compared with the conventional single chaos map based encryption system, the algorithm proposed in this paper enlarges the key space, extends the period and improve the linear complexity of the key stream under precision restricted condition. The theoretical analysis and experimental results indicate that the system is strong against various common attack methods.

An accelerated algorithm of constructing general high-order mandelbrot and julia sets

A series of high order Mandelbrot and Julia fractal images of complex map

A Chaotic Dynamical Model for Internet Traffic

f:zleftarrow{mathcal{}z}^n+c(n>2,nin{N})

On the Chaotic Phenomena Analysis of Multipath Fading Channel

are constructed by using escape time algorithm. Topology invariance and the relation between period bud distribution and mapping orders are found through lots of computer mathematic experiments. The escape time algorithm is improved on basis of the rotation symmetric property of Manderlbrot and Julia sets, and then a rotation escape time algorithm is established. The high-order Mandelbrot and Julia sets fractal images are generated by using Web oriented Java Applet. Therefore the complexity of computer simulation under complex conditions is greatly reduced. The application of Java technology provides an Internet-based distribution platform for chaos-fractal theory study.

A Fractal-Based Simulation Scheme for Securities Business of China

This paper analysis the chaotic dynamical properties of network traffic based on the self-similarity characteristic of the Internet traffic. The phase space of the traffic time serials is reconstructed and the correlation dimension is analyzed, which indicate that the dynamical system has finite degree of freedom and a positive maximum Lyapunov exponent. The chaotic characteristic of the traffic is demonstrated and the nonlinear evolution mechanism is observed. Finally, the traffic signals are reconstructed by using fractal interpolation algorithm and gaining reasonably accurate replications.