Browsing by Author "Chen, Yen-Cheng"

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A practical authentication protocol with anonymity for wireless access networks
(2011-10-01)
Chen, Yen-Cheng
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Chuang, Shu-Chuan
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Yeh, Lo-Yao
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Huang, Jiun-Long
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資訊工程學系
The use of anonymous channel tickets was proposed for authentication in wireless environments to provide user anonymity and to probably reduce the overhead of re-authentications. Recently, Yang et al. proposed a secure and efficient authentication protocol for anonymous channel in wireless systems without employing asymmetric cryptosystems. In this paper, we will show that Yang et al.'s scheme is vulnerable to guessing attacks performed by malicious visited networks, which can easily obtain the secret keys of the users. We propose a new practical authentication scheme not only reserving the merits of Yang et al.'s scheme, but also extending some additional merits including: no verification table in the home network, free of time synchronization between mobile stations and visited networks, and without obsolete anonymous tickets left in visited networks. The proposed scheme is developed based on a secure one-way hash function and simple operations, a feature which is extremely fit for mobile devices. We provide the soundness of the authentication protocol by using VO logic. Copyright (C) 2010 John Wiley & Sons, Ltd.
ABACS: An Attribute-Based Access Control System for Emergency Services over Vehicular Ad Hoc Networks
(2011-03-01)
Yeh, Lo-Yao
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Chen, Yen-Cheng
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Huang, Jiun-Long
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資訊工程學系
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Department of Computer Science
In this paper, we propose an Attribute-Based Access Control System (ABACS) for emergency services with security assurance over Vehicular Ad Hoc Networks (VANETs). ABACS aims to improve the efficiency of rescues mobilized via emergency communications over VANETs. By adopting fuzzy identity-based encryption, ABACS can select the emergency vehicles that can most appropriately deal with an emergency and securely delegate the authority to control traffic facilities to the assigned emergency vehicles. Using novel cryptographic preliminaries, ABACS realizes confidentiality of messages, prevention of collusion attacks, and fine-grained access control. As compared to the current PKI scheme, the computational delay and transmission overhead can be reduced by exploiting the advantages afforded by message broadcasting, which is heavily used in ABACS. The performance evaluation demonstrates that ABACS is a suitable candidate for realizing emergency services via VANETs.
PAACP: A portable privacy-preserving authentication and access control protocol in vehicular ad hoc networks
(2011-03-15)
Yeh, Lo-Yao
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Chen, Yen-Cheng
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Huang, Jiun-Long
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資訊工程學系
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Department of Computer Science
Recently, several studies addressed security and privacy issues in vehicular ad hoc networks (VANETs). Most of them focused on safety applications. As VANETs will be available widely, it is anticipated that Internet services could be accessed through VANETs in the near future. Thus, non-safety applications for VANETs would rise in popularity. This paper proposes a novel portable privacy-preserving authentication and access control protocol, named PAACP, for non-safety applications in VANETs. In addition to the essential support of authentication, key establishment, and privacy preservation, PAACP is developed to provide sophisticated differentiated service access control, which will facilitate the deployment of a variety of non-safety applications. Besides, the portability feature of PAACP can eliminate the backend communications with service providers. Therefore, better performance and scalability can be achieved in PAACP. (C) 2010 Elsevier B.V. All rights reserved.
V - and W - Band Substrate Integrated Waveguide (SIW) Mechanical Switch
(2018-06-01)
Wei, Shih-Chiang
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Yang, Chin-Hao
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Chen, Yen-Cheng
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Chen, Ting-An
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Chang, Chi-Yang
This paper presents high-isolation single-polesingle-throw (SPST) and single-pole-double-throw (SPDT) substrate integrated waveguide (SIW) mechanical switches in V-and W-bands. Four via holes with the proposed ring-andcross etching patterns on the top side are placed in the middle of SIW path to block or pass the waves. As the ring-and-cross etching patterns being short-circuited, the via holes block the waves just like stockades do, in other words, turning the switch to OFF mode. And the ring-and-cross etching pattern makes the via holes invisible, turning the switch to ON mode. The V-and W-band SIW SPST and SPDT switches are designed and fabricated. The switches show the measured performances of better than 45-dB isolation for SPST and better than 50-dB isolation for SPDT, for V-band operation, and a better than 50-dB isolation for both SPST and SPDT for W-band operation.