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The fabrication and characterization of 4H-SiC Schottky metal-semiconductor-metal(MSM) photodetectors are reported in this paper. The current-voltage(I-V), capacitance-voltage(C-V) and spectral response characterization of the photodetectors are measured at room temperature. The dark current is 1.24×10−8A at 4V bias, and the average capacitance is 82.66pF at 0–5V voltage range. The spectral response range is from 250nm to 350nm wavelength, and the highest responsivity appears at the wavelength of 280nm. The results indicate that the 4H-SiC photodetectors are visible-blind.

Recently, remote user authentication schemes are implemented on elliptic curve crypto-System (ECC) to reduce the computation loads for mobile devices. However, most remote user authentication schemes on ECC are based on public-key cryptosystem, in which the Public key in the system requires the associated certificate to prove its validity. Thus, the user needs to perform additional computations to verify the certificate in these schemes. In addition, we find these schemes do not provide mutual authentication or a session key agreement between the user and the remote server. Therefore, we propose an ID-based remote mutual authentication with key agreement scheme on ECC in this paper. Moreover, we adopt multi-servers to realize the scheme’s scalability. Compared with the related works, the proposed scheme is more efficient and practical for distributed or portable devices.

The article presents a distributed group key agreement protocol based on Validated-BD Protocol and logical tree. Although the amount of communication and computation are increasing at the beginning of the proposed protocol, the protocol can guarantee honesty of participants and decreases the amount of communication and computation when members change. It can deal with members’ changing efficiently. The protocol is constructed by Validated-BD protocol, which can prevent active attack from internal malicious members. Compared with previous protocol, our protocol is more efficient and scalable for distributed application.

In this paper, the technology of trusted boundary based on port trust value is discussed. When IP phones are connected to the existing switch-based campus area network, PC is connected to the access port of IP phone. To avoid IP phone is disconnected from the network and PC is directly into the switch port, trusted boundary based on port trust value is applied. In an IP PBX, trusted mode or untrusted mode are supported by IP phone, which is trusted and untrusted. The final run-time port trust on any port is dependent on five decisive factors: Quality of Service, Common Open Policy Service, trust-device type, Cisco Discovery Protocol and phone's presence on the port. In a typical campus area network with IP phones, trusted boundary based on port trust value is configured. Trusted boundary can ensure the security of the port to which IP phone is connected.

Privacy and security solutions require the protection of personal information so that it may not be disclosed to unauthorized participant for illegal purposes. It is a challenge to address these issues in networks with strong constraints such as Ad Hoc network. The security increase is often obtained with a quality of service (QoS) decrease. We propose in this paper a solution that provides at the anonymity, security to Ad Hoc network with a limited impact on QoS. This method could be efficient against some viral attacks. We also give some security proofs of our solution for Ad Hoc networks.

The paper presents a new password authentication and key-exchange protocol suitable for remote user without verification table and exchanging keys over an untrusted network. The new protocol resists dictionary attacks mounted by either passive or active network intruders,even an insider attacker, allowing, in principle, even weak password phrases to be used safely. It also offers perfect forward secrecy, which protects past sessions and passwords against future compromises. Finally, user passwords are stored in a form that is not plaintext-equivalent to the password itself, so an attacker who captures the smart card cannot use it directly to compromise security and gain immediate access to the host. The proposed protocol’s security, simplicity, and speed make it ideal for a wide range of real-world applications in which secure password authentication is required. Compared with the related works, the proposed scheme is more efficient and practical for distributed or portable devices.

This paper proposes a novel method to characterize unwanted email traffic. Research object is a significant, diverse, and representative set of Internet email traffic, The email session we choose is based on an extended deterministic finite automata (EFSA) model, then choose some parameters to capture email traffic characterization. The method is applied to two different volumes of email traffic data captured respectively at an email gateway of a LAN and a country-edged core router of a large ISP (Internet Service Provider) in China, then we analyze the characteristics and causes of those unwanted traffic. The results show that our method is effective, administrator can use it to design effective rules and strategies to reduce unwanted traffic.

With the development of application of the peer-to-peer networks, the problem of the privacy preservation has aroused extensive concern. Though many previous researches have focused on the realization of the anonymous communications, these anonymous technologies usually need complex structures which increase the cost of maintenance and the difficulty of management, and prolong the transmission delay. Aimed at the privacy preservation of searching content in P2P network, especially the network without searching server, a concealment searching model based on one-way function and Soundex algorithm is proposed. It can protect searching content of peers and resist attacks of snooping, replay, disguise and so on, meanwhile the model support accurate search and fuzzy search. According to the analysis, this concealment searching model achieves relatively high security as well as searching effectively.

Recently, Tsai et al. have proposed a multi-server authentication protocol. They claimed their protocol is secure and can withstand various attacks. But we found some security loopholes in the protocol. Accordingly, the current paper demonstrates that Tsai’s protocol does not provide perfect forward secrecy and is susceptible to a Denning-Sacco attack and Server spoofing. We then present an enhanced protocol to isolate such problems.

Data compression is popularly applied to communication systems and computer systems. Ziv-Lempel coding is a class of popular data compression method and uses dictionary which includes the tendency of the source data. The dictionary is classified into two types, dictionary including local tendency of the source data and the one including global tendency of the source data. The compressed data have a problem that they are very sensitive to errors; and therefore, several error recovery methods for data compression have been proposed. This paper proposes error recovery method for data compression method which uses two types of dictionaries. The compression method is proposed by the authors and uses both local and global tendency of the source data. Computer simulations shows that compression ratio of the proposed compression method is better than existing Ziv-Lempel coding and its variations. Error recovery capability of the proposed code is high and the influence of the error is almost less than 10 percent.

Zero-copy means on any network node, during message transmission, there is no data copy among memory segments and all messages transmission are operated directly between user application space and outside of network through network interfaces. By DMA technology, network interface devices can store data packets into the address where it can be accessed directly by user application, the data packets copy operation is removed in kernel and reducing the data transmission path. By working together with TOE technology, it can drop the communication delay effectively and save a lot of CPU cost. In this paper, we based on Linux (kernel version 2.6.11), by modifying its network device driver snull.c (attached in Linux Device Driver version 3), to implement the memory mapping between Linux kernel space to user application space. The main method we used is the combination of MMAP and PROC procedures, and at the end, we also introduce the implementation of test program and the test strategies. The test results show us that the applications can access the applied memory of kernel by mapping

Purpose-to remove CPU from heavy services of protocol processing, and alleviate the bottlenecks of communication system to suit for the high speed network. Design a new architecture for TOE which includes TOE design, TOE data stream transfer, TOE performance test and TOE security, etc. Methodology-by analysis and design with Linux specialties binding to functions of ML403 development version, to code or modify portion of kernel code and use VHDL to design the hardware section. Result-by analysis the design requirements of TCP/IP offload, to simplify the protocol stack of TCP/IP, and finally to give out a ML403 based solution for TOE architecture design, to build a system experiment platform and last we draw some conclusions and some test results. Conclusion-Although the results show that the performance improving is not much, the simple success of test indicates that this solution is correct and potential. It will contribute to the performance improvement of whole communication system and popularization to the TOE network card.