Tiegang Gao

A HYPERCHAOS GENERATED FROM CHEN'S SYSTEM

This paper presents a new hyperchaotic system, obtained by adding a controller to the second equation of the three-dimensional autonomous Chens chaotic system. The hyper-chaos system undergoes a change from hyperchaos to limit cycle when the parameter varies. The system is not only demonstrated by computer simulations but also verified with bifurcation analysis.

An Improved Image Encryption Algorithm Based on Hyper-Chaos

Motivated by a recently proposed hyper chaos based image encryption algorithm and some successful attacks on it, an improved image algorithm is proposed in this paper. In the proposed algorithm, key-stream depends on the plaintext and the ciphered text; this makes it different in every encryption process, so it is more like a One Time Pad, which is in formation theoretically secure. Some simulations are given to demonstrate that the suggested encryption algorithm of image has the advantages of large key space and high security, and moreover, the distribution of grey values of the encrypted image has a random-like behavior, and some security analysis are also given to show that the proposed algorithm can resist some attacks.

A Novel Adaptive Reversible Watermarking Algorithm Based on Wavelet Lifting Scheme

A new adaptive reversible watermarking algorithm based on wavelet lifting scheme is proposed in this letter. In the algorithm, watermarking image is embedded in the sub-band 1 LL generated from 1-level wavelet lifting scheme, and the position information with small size is kept as a secret matrix, the threshold value can be adaptively selected according to the peaksignal to noise rate, such that watermarked image has better visual effect, the novelty of the algorithm lies in that it not only is reversible, but also it is robust to JPPEG compression attack, this is seldom discussed in existing relative literatures. The experimental results show the effectiveness of the scheme in the end. Keywords-reversible watermarking; wavelet lifting scheme; robustness; peak-signal to noise rate

A new image authentication based on reversible watermarking algorithm

A new image authentication based on reversible watermarking algorithm is proposed in this paper, which first divided the original image into two parts, one part is used to extract image features, based on difference expansions, and the other part is used to embed the data extracted from itself and the first part. Experimental results show that image with embedded data can be restored completely and the positions of the tampered parts can be located correctly.

Adaptive synchronization of totally different and uncertain hyper-chaos

This Letter discusses synchronization problem of two new and totally different hyper-chaoses when ten parameters of the drive and response system are fully unknown and different. Based on Lyapunov stability theory, an adaptive control law with parameters update laws is derived such that the states of two different hyper-chaotic systems can asymptotically be synchronized.

Realizing of Reduced-order Synchronization of Chaos with Hyper-chaos Based on Active Control

Generalized reduced-order synchronization between chaotic system and hyper-chaos based on active control was studied in this paper. It is shown that dynamical evolution of third-order oscillators can be synchronized with the canonical projection of a fourth-order hyper-chaos generated through non-singular states transformation from Rossler hyper-chaos system. In this sense, the synchronization discussed here expands the scope of reduced-order synchronization studied in relative literature. Simulation results are provided to verify the operation of the proposed synchronization scheme