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The visual signal processing mechanism of humans and mammals is precise and complex, better than most current machine vision systems. Visual illusion can show the cognitive functions and mechanisms of the visual system from a unique perspective which are of great significance to the development of computer vision. Firstly, the Gabor filter perfectly simulates the direction and spatial frequency selectivity of the visual cortex cells, thus successfully explaining why the Einstein-Monroe picture has two interpretations when viewing distance is changed and verifying the multi-scale characteristics of the visual neural network. Secondly, by means of nonlinear dynamics, the visual neural dynamics system based on the multi-scale background environment is established to reproduce optical illusions like Herman grid illusion. By understanding the mechanism of visual illusion, it can provide convenient experimental means for realizing the multi-modal information integration of multi-scale neural network and theoretical research of memory fusion model.

This paper deals with the cryptographic performance of Rijndael and RC6 algorithms in real environment. The cryptographic performance of Rijndael and RC6 algorithms is evaluated from the diffusion, confusion, and space-time complexity of them. The diffusion and confusion of them are quantitatively measured by using the avalanche effect and runs test. The time performance metrics are encryption and decryption speeds while space performance metric is memory utilization. The experimental results show that both Rijndael and RC6 have good avalanche properties for the plaintext and key. They are very close to the SAC (Strict Avalanche Criterion). The cipher texts of Rijndael and RC6 have good randomness and unpredictability from the results of runs test. However, the encryption speed of RC6 algorithm is much faster than that of Rijndael algorithm in the same experimental conditions, and is independent of the key length. The encryption and decryption speed of Rijndael are asymmetric although Rijndael algorithm is a symmetric block cipher. Meanwhile, RC6 needs more CPU and memory resources than Rijndael algorithm. So the use of RC6 is beneficial where high encryption speed is required while Rijndael is beneficial where memory resource is key concern.

Nowadays, LTE (Long Term Evolution) is widely used. The MAC layer plays an important role in the quality of LTE transmission. Spectrum efficiency, frame loss rate, throughput and delay are selected as the primary evaluation criterion of the performance of LTE system. This paper deals with the performance of MAC layer in the LTE networks. The system-level performance analysis of MAC layer is conducted through the Network Simulator 3. An orthogonal experimental design is adopted to evaluate the effect of various key factors on the MAC performance of LTE network. These factors mainly include the bandwidth, MAC layer scheduling algorithm, customer density, partial OFDM algorithm and other factors. We also look for a reasonable LTE communication scheme for different conditions to make sure that the system has good performance such as a higher throughput, a smaller end-to-end delay, a smaller delay jitter and a lower frame loss rate.

NNSF of China [60076015]; key science project of Fujian Province, China [2009H0037]; science project of Xiamen City, China [3502Z20081073]

The security of the symmetric probabilistic encryption scheme based on chaotic attractors of neural networks is analyzed and discussed. Firstly, the key uniqueness is proved by analyzing the rotation transform matrix to avoid the attack of the equivalent key. Secondly, the distributed uniformity of the numbers “0” and “1” in the corresponding attracting domain for every chaotic attractor is analyzed by the statistics method. It is testified that the distributed uniformity can be kept if the synaptic matrix of the neural network is changed by a standard permutation matrix. Two annotations based on the results above are proposed to improve the application security of the encryption algorithm.

The proposed perceptual mask is based on the singularity of cover image and matches very well with the properties of the human visual system. The cover colour image is decomposed into several subbands by the wavelet transform. The watermark composed of chaotic sequence and the covert image is embedded into the subband with the largest energy. The chaos system plays an important role in the security invisibility and robustness of the proposed scheme. The parameter and initial state of chaos system can directly influence the generation of watermark information as a key. Moreover, the watermark information has the property of spread spectrum signal by chaotic sequence to improve the invisibility and security of watermarked image. Experimental results and comparisons with other watermarking techniques prove that the proposed algorithm is effective and feasible, and improves the security, invisibility and robustness of watermarking information.

Authenticating wireless devices based on PARADIS technique draws increasing research interest recently, providing security access services in wireless networks. This paper provides an overview of various schemes for PARADIS identification using physical layer characteristics. Firstly, this work systematizes the existing knowledge on this topic for a better understanding of PARADIS device identification, its implications on the analysis and design of security solutions in wireless mobile networks, and possible applications. Secondly, we review the development progress of PARADIS identification techniques, discuss the merits and demerits of existing PARADIS identification schemes and provide a summary of the current state of the art. Moreover, we propose a new authentication scheme based on PRARDIS and discuss its security and feasibility in the SAE/LTE application. We also highlight the open problems of PRARDIS and motivate future works.

Based on chaotic maps, a novel robust watermarking algorithm is presented in this paper. The proposed approach improves the invisibility, robustness and security of traditional watermarking algorithm by using chaotic sequences. Taking advantage of the characteristics of extreme sensitivity to initial conditions, Chebyshev maps are used to generate substantially different watermarks as a key. This technique has been shown to offer an added security advantage over the more traditionally generated watermarks created from pseudorandom sequences, in that only the function seed needs to be stored. Various kinds of images are selected as watermark images in order to prove the fidelity of the proposed scheme. Simulation of the algorithm is performed on different types of images, and the results are compared with existing algorithms. Results show that the proposed scheme is simple and applicable, and can resist many attacks such as JPEG compression, rotation, cropping and noising.

In a freeway vehicular ad hoc network (VANET) environment, an efficient ad hoc routing protocol plays a very important role to enhance the safety of passengers. This paper presents the latest result of simulation model of three mobile ad hoc routing protocols: destination-sequenced distance-vector protocol (DSDV), dynamic source routing (DSR) and ad hoc on-demand distance vector (AODV). The performance of three protocols under constant bit rate traffic is evaluated and compared with five quality indices. The simulation results show that both the reactive routing protocols, DSR and AODV, have better performance than the proactive routing protocol DSDV. DSDV has largest packet loss rate and smallest system throughput among the three protocols. This paper also shows that the effect of varying mobility has undeniably influenced the performance of both reactive routing protocols. DSR is better in the protocol overhead than AODV. However, there is critical jitter variation in the DSR. As a whole, AODV is more appropriate than DSR for the freeway VANET.

A new routing algorithm applicable for client network of Wireless Mesh Network (WMN), called hybrid maintenance routing (HMR), is presented. WMN share common features with ad hoc networks, the routing protocols developed for ad hoc networks can be applied to WMN. Based on DSR (dynamic source routing), HMR applies multi-path routing to improve the routing fault tolerance of client networks of WMN. Route maintenance has been the main area of protocol in ad hoc network. There are two kinds of approach for route maintenance, the proactive routing maintenance and the on-demand reactive routing maintenance. A hybrid maintenance approach which combines the proactive routing maintenance and the reactive routing maintenance will improve the validity of multi-path without increasing too much overhead.

SSL (secure sockets layer) protocol is one of key technologies to keep userpsilas data in secure transmission via Internet. This paper is present to analyze the security of SSL protocol and propose a new scheme of SSL protocol configured in the Linux operating system (OS). The experimental results show that the proposed scheme is feasible and practical as a secure solution for Web-based communication, and the SSL protocol is compatible to the other protocol in application layer via proper configuration.

In this paper proposes a new wavelet watermark technique based on the linear bit expansion. To ensure the security of the watermark, enlarged watermark by applying linear bit expansion is inserted in a given intensity to a low frequency sub-band of the image which is wavelet transformed after the Arnold Transformation. Using F norm function to detect the presence of watermark is applied which is different from existing methods. The experimental results verify that the proposed watermarking technique has outstanding quality in regards to fidelity and robustness.

Recently a new piecewise linear chaotic map (PLCM) with a segment number parameter (SNP) has been proposed. Its cryptographical properties including sensitivity to initial point and randomness of sequences obtained by iterating are very valuable in designing cryptosystems. The properties of digital PLCM with SNP are different from the continuous ones. In this paper, these cryptographical properties were analyzed when the map was realized in finite computing precision. The functional relationship among SNP, implementation precision, the number of iterating was developed in order for sensitivity to initial point; the statistical properties were also investigated. The analysis result will be valuable for the research on chaotic cryptography.

A Diffie-Hellman public-key cryptography based on chaotic attractors of neural networks is described in the paper. There is a one-way function between chaotic attractors and initial states in an Overstoraged Hopfield Neural Network (OHNN). If the synaptic matrix of OHNN is changed, each attractor and its corresponding domain of initial state attraction will be changed. Then, we regard the neural synaptic matrix as a trap door, and change it with commutative random permutation matrix. A new Diffie-Hellman public-key cryptosystem can be implemented, namely keeping the random permutation operation of the neural synaptic matrix as the secret key, and the neural synaptic matrix after permutation as public-key. In order to explain the practicability of the encryption scheme, Security and encryption efficient of the scheme are discussed. The scheme of application for Internet secure communications is implemented by using Java program. The experimental results show that the proposed cryptography is feasible, and has a good performance of encryption and decryption speed to ensure the real time of IPng secure communications.

Password authentication is one of the most convenient and frequently used mechanisms to provide secure remote access control. In this paper, a pairing-based password authentication scheme which draws on the experience of two previous researches is proposed, and the detailed authentication phases which utilise the good properties of bilinear pairing are illustrated. Meanwhile, strict cryptanalysis is made to clarify the good security and functionality features of the proposed scheme in defending various attacks. Besides that, some flaws of a previous scheme are analysed and theoretical comparison of the computation cost with that scheme is made. Furthermore, experiments are conducted properly and the results are shown to explain the high efficiency of the proposed scheme.