Security Enhancement of Robust User Authentication Framework for Wireless Sensor Networks

In order to relvedy the security weaknesses of a robust user authentication framework for wireless sensor networks, an enhanced user authentication framework is presented. The enhanced scheme requires proof of the possession of both a password and a snort card, and provides more security guarantees in two aspects： 1） it addresses the untmceability property so that any third party accessing the communication channel cannot link two authentication sessions originated from the same user, and 2） the use of a smart card prevents offiine attacks to guess passwords. The security and efficiency analyses indicate that our enhanced scheme provides the highest level of security at reasonable computational costs. Therefore, it is a practical authentication scheme with attractive security features for wireless sensor networks.

ON CLASSICAL BCH CODES AND QUANTUM BCH CODES

It is a regular way of constructing quantum error-correcting codes via codes with self-orthogonal property, and whether a classical Bose-Chaudhuri-Hocquenghem (BCH) code is self-orthogonal can be determined by its designed distance. In this paper, we give the sufficient and necessary condition for arbitrary classical BCH codes with self-orthogonal property through algorithms. We also give a better upper bound of the designed distance of a classical narrow-sense BCH code which contains its Euclidean dual. Besides these, we also give one algorithm to compute the dimension of these codes. The complexity of all algorithms is analyzed. Then the results can be applied to construct a series of quantum BCH codes via the famous CSS constructions.

A New Provably-Secure Key Agreement Protocol for Roaming in Mobile Networks

Protocols for authentication and key establishment have special requirements in a wireless environment. This paper presents a new key agreement protocol HAKA （home server aided key agreement） for roaming scenario. It is carried out by a mobile user and a foreign server with the aid of a home server, which provides all necessary authentications of the three parties. The session key can be obtained by no one except for the mobile user and the foreign server. HAKA is based on Diffie-Hellman key exchange and a secure hash function without using any asymmetric encryption. The protocol is proved secure in Canetti-Krawczyk （CK） model.

ALTERNATING DIRECTIONFINITE ELEMENT METHOD FORSOME REACTION DIFFUSION MODELS

This paper is concerned with some nonlinear reaction - diffusion models. To solve this kind of models, the modified Laplace finite element scheme and the alternating direction finite element scheme are established for the system of patrical differential equations. Besides, the finite difference method is utilized for the ordinary differential equation in the models. Moreover, by the theory and technique of prior estimates for the differential equations, the convergence analyses and the optimal L2- norm error estimates are demonstrated.

ATTACKS ON REAL POLYNOMIAL TYPE PUBLIC-KEY CRYPTOSYSTEMS AND DISCUSSION ON RELATED PROBLEMS

The real polynomial type public-key cryptosystems are broken up by computing the equivalent secure keys, then some computational problems related to securities of cryptosystems are discussed.

0,1 distribution in the highest level sequences of primitive sequences over Z2e

In this paper, we discuss the 0, 1 distribution in the highest level sequence ae-1 of primitive sequence over Z2e generated by a primitive polynomial of degree n. First we get an estimate of the 0, 1 distribution by using the estimates of exponential sums over Galois rings, which is tight for e relatively small to n. We also get an estimate which is suitable for e relatively large to n. Combining the two bounds, we obtain an estimate depending only on n, which shows that the larger n is, the closer to 1/2 the proportion of 1 will be.

Using Micro-Level Data to Evaluate Infrastructure of the Walking Environment Around Bus Rapid Transit Stations:A Case Study of Xiamen,China

China has experienced rapid car-oriented suburbanization during the past decades and is facing emerging challenges such as traffic congestion,air pollution,and even health threats.Learning from North American cities,Chinese cities have started adopting and implementing a Transit-Oriented Development(TOD) strategy,which encourages the transit ridership and walking trips by creating a pedestrian-friendly urban environment.Although much research has examined the walking environment in various neighborhoods or communities,few existing studies have examined the walking environment around transit stations,especially using micro-level data,such as walking infrastructure variables.This research chooses several infrastructure variables that are critical for pedestrians to investigate the walking environment around stations of the Bus Rapid Transit(BRT) No.1 Line in Xiamen City,China.This study defines a half mile buffer centered on each station as the spatial unit of analysis.The Geographic Information System(GIS) and field audits are employed to measure the characteristics of the infrastructure for pedestrians in each spatial unit of analysis.The results of this analysis can help assess the existing conditions of the infrastructure for pedestrians in each station area,which might need to be added or improved.The findings will not only provide empirical support for improving TODs in Xiamen,but also offer a lesson on how areas around transit stations could be retrofitted to improve the pedestrian environment.

Reversible Watermarking in JPEG Images Based on Modified RZL Codes and Histogram Shift

Reversible watermarking has extensive applications in fields such as medical data management and forensic enforcement. In this article, we propose a modified reverse zero-run length （RZL） coding method for reversible watermarking, which intro- duces fewer modifications to cover than previous ones under the same embedding rate. By combining the coding method with his- togram shift and quantization table modification strategy, we pro- pose a novel reversible data hiding algorithm for JPEG images. Compared with previous art, when embedding the same payload, our method has an improvement of at least 2 dB in stego image＇s quality, which proves the effectiveness and advantage of our algo- rithm.