Wang Ying-long

A novel image encryption scheme based on chaotic maps

In this paper, a novel image encryption scheme based on chaotic maps is proposed. By combining XOR operations and circular bit shift operation, the security of this encryption algorithm is enhanced effectively. Two chaotic maps are adopted in the proposed scheme. One creates a binary stream for XOR operation, and the other creates some random numbers which are used to determine the circular bit shift. First the pixel values of the plain-image are modified randomly by the classical chaotic masking technique, namely XOR operation from the first block to the last block, and then the modified image is encrypted by the circular bit shit operation from the last block to the first block in the inverse order. The security of the proposed encryption scheme is detailed analyzed, and the experimental results show that the algorithm has a high security performance and a good efficiency.

A flexible and secure image compression coding algorithm

In this paper, we investigate the problem of efficient image data encryption and compression. Based on feedforward-feedback nonlinear dynamic filter (FFNDF) and employing random arithmetic coding, a novel image encryption scheme integrated with the set partitioning in hierarchical trees (SPIHT) has been proposed. The FFNDF is employed to generate pseudorandom sequences which determine the mapping the interval position in the process of arithmetic coding. By encoding the bits obtained from different passes in the SPIHT algorithm with adaptive random arithmetic coding, we obtain a flexible secure image compression coding scheme. Also, the scheme accommodates features of progressive coding of the SPIHT. Theoretical analysis and experimental results show that the scheme has good cryptographic security and perceptual security, and it does not affect the compression efficiency apparently. The efficiency and security of the encryption scheme makes it an ideal choice in various applications such as total encryption, selective encryption, conditional access.

A IPv6 Network Performance Test System using Multi-Agent

The Internet Engineering Task Force (IETF) has introduced IPv6 with a mission to meet the growing demands of the future Internet. IPv6 is more and more emphasized and moving from the pilot phase to the practical application. In the process of deploying IPv6, performance is one of the key issues to be considered. Test is an effective method to understand IPv6 network performance. We need scalable and available tools to measure IPv6 network performance, but the few existing network performance test software support IPv6. So through the introduction of multi-agent technology, a distributed IPv6 network performance test model integrated with centralized control is proposed. We describe architecture and workflow of the model thoroughly, and a IPv6 network performance test system is designed and implemented based on the model. Finally, using our system, we measure IPv6 performance metrics on CERNET2 which is the largest pure IPv6 network in the world presently. The final experiments show that it is necessary to implement a IPv6 network performance test system and that our system is scalable and available for IPv6 network performance test.