In 2009, Wang et al. argued that Das et al.'s scheme is vulnerable to stolen smart card attack if an attacker obtains the smart card of legitimate user and chooses any random password. Then the attacker gets through the authentication process to get access of the remote server. Therefore, Wang et al. proposed an improved scheme to preclude the weaknesses of Das et al.'s scheme. However, we found that Wang et al.'s scheme is vulnerable to impersonation attack, stolen smart card attack and offline password guessing attack. This paper improves Wang et al.'s scheme to resolve the aforementioned problems, while keeping the merits of different dynamic identity based authentication schemes.

An improvement of Wang et al.'s authentication scheme using smart cards

In 2004, Das et al. proposed a dynamic identity based remote user authentication scheme. They claimed that their scheme is secure against different attacks. Unfortunately, many researchers demonstrated that Das et al. scheme is vulnerable to various attacks. Furthermore, this scheme does not achieve mutual authentication and thus can not resist malicious server attack. In 2005, Liao et al. improved Das et al.'s scheme and claimed that the improved scheme achieves mutual authentication, withstand password guessing attack and insider attack. In 2006, Yoon and Yoo demonstrated a reflection attack on Liao et al.'s scheme that breaks the mutual authentication. In this paper, we found that Liao et al.'s scheme is also vulnerable to malicious user attack, impersonation attack, stolen smart card attack and offline password guessing attack. Moreover, Liao et al.'s scheme does not maintain the user's anonymity and its password change phase is insecure. This paper presents a secure dynamic identity based authentication scheme using smart cards to resolve the aforementioned problems, while keeping the merits of different dynamic identity based authentication schemes.

An improvement of Liao et al.'s authentication scheme using smart cards

In practice, the single sign-on system is likely to suffer password attack and replay attack, etc. For the purpose of resolving these problems, a new single sign-on scheme is raised, which is based on dynamic password method. In the new scheme, a specific design is given, and the security of this scheme is analyzed in details. In this scheme, through the universal dynamic password authentication, the user can visit all the services in the visiting range. At the same time, the scheme implements the connect authentication between the client and application servers.

Design on a Single Sign-On Scheme

Saliency Region and Motion Characteristics Combined Video Quality Assessment.

With the rapid development of Internet and multimedia, there is new challenge on streaming media processing and transmission. On one hand, the demand for the quantity and quality of multimedia resources are getting higher, which requires the matching capabilities of data storage and transmission. On the other hand, restricted to the computer's processing power, heterogeneous network environment, network bandwidth, terminal processing capacity and so on, the limited computing resources can only be allocated to the important visual information for analysis and processing. In order to accurately describe the important visual information, this paper proposes a video motion description method which is in line with human visual characteristics. Combined with the human visual perception characteristics and eye movement analysis, three characteristics are introduced: motion intensity, motion complexity and motion density. The dynamic characteristics of the frame is described by weighting the object and background motion vector intensities. The objective motion value can accurately reflect the human visual perception.

Research on video motion characteristics extraction and description based on human visual characteristics

For solve the defect of based on time and based on event,This paper propose a new dynamic password authentication scheme.Dynamic password is correlated to the number of logging-on,so it is different each time.It's core is automate with output.Automate run both on client and server.Since the number of logging-on change synchronally,so the password between client and server is same.This paper prove the password satisfy constraint of dynamic password based on independent analysis of password.New scheme have two work mode:logging-on mode and calibration mode.Calibration mode can restore the synchronization between client and server after two handshakes.Calibration is very easy,user can

A new dynamic password authentication scheme

This paper proposes a scalable video stream sorting approach based on content-aware in order to improve the transmission efficiency and the video broadcast quality.According to the human subjective perception of changing scenes,the model is established to describe the dynamic characteristics of the video.Object and background motion vectors are weighted adaptively.The video packets on the frame level are tagged and sorted by the approach mentioned in this paper,which is combined with the video coding structure and the rate-distortion model.Experimental results show that the method can accurately describe the video dynamic characteristic and effectively improve the video broadcast quality and human subjective perception.This method is more significant for the complex video sports scene.

Zhang Ji-hong

Papers

A new dynamic password authentication scheme

Content-Aware Based Sorting Approach of Scalable Video Bit Stream