Gwan‐Hwan Hwang

National Taiwan Normal University

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Tao-Ku Chang

National Dong Hwa University

Jenq Kuen Lee

National Tsing Hua University

Yu‐Cheng Hsiao

Taipei Medical University

Chi Wu‐Lee

Institute for Information Industry

Hung-Fu Chen

Institute of Information Science, Academia Sinica

Roy Dz-Ching Ju

MediaTek (China)

Dz-Ching Ju

Hewlett-Packard (United States)

Jenn‐Zjone Peng

National Taiwan Normal University

Che-Sheng Lin

National Taiwan Normal University

Chung-Chia Li

National Taiwan Normal University

Cooperative Institutions

Ensemble Therapeutics (United States)

162

National Taiwan Normal University

National Formosa University

National Yang Ming Chiao Tung University

Sichuan University

National Taiwan University

National Tsing Hua University

National Cheng Kung University

Chinese Academy of Sciences

Chunghwa Telecom (Taiwan)

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A Semidecentralized PKI System Based on Public Blockchains with Automatic Indemnification Mechanism

Security and Communication Networks (2021)

Gwan‐Hwan Hwang Tao-Ku Chang Hung-Wen Chiang

The PKI framework is a widely used network identity verification framework. Users will register their identity information with a certification authority to obtain a digital certificate and then show the digital certificate to others as an identity certificate. After others receive the certificate, they must check the revocation list from the CA to confirm whether the certificate is valid. Although this architecture has a long history of use on the Internet, significant doubt surrounds its security. Because the CA may be attacked by DDoS, the verifier may not obtain the revocation list to complete the verification process. At present, there are many new PKI architectures that can improve on the CA’s single point of failure, but since they still have some shortcomings, the original architecture is still used. In this paper, we proposed a semidecentralized PKI architecture that can easily prevent a single point of failure. Users can obtain cryptographic evidence through specific protocols to clarify the responsibility for the incorrect certificate and then submit the cryptographic evidence to the smart contract for automatic judgment and indemnification.

Certificate

Root certificate

Revocation list

Revocation

Trust anchor

Implicit certificate

10.1155/2021/7400466

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Citations (4)

A model‐free and state‐cover testing scheme for semaphore‐based and shared‐memory concurrent programs

Software Testing Verification and Reliability (2014)

Gwan‐Hwan Hwang C.-H. Lin Teng‐Shuo Lee Chi Wu‐Lee

SUMMARY In this paper, we present a new framework for performing dynamic testing of semaphore‐based and shared‐memory concurrent programs. The proposed scheme only has to analyse the synchronization sequences (SYN‐sequences) that are collected during the dynamic testing of the concurrent program – static analysis of the syntax and semantics of the target concurrent program is unnecessary. A model checker is not needed to explore the feasible interleavings of the execution of the concurrent program. If the number of feasible SYN‐sequences of the tested concurrent program is finite, our scheme can perform dynamic testing of all the feasible SYN‐sequences. If the tested concurrent program has an infinite number of SYN‐sequences, state‐cover testing of the target program can be performed (if the execution states of the target concurrent program are finite). The implementation and experimental results obtained with real codes and some benchmark programs demonstrate the feasibility of the proposed scheme. Copyright © 2014 John Wiley & Sons, Ltd.

Semaphore

Benchmark (surveying)

Concurrent computing

10.1002/stvr.1520

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Citations (3)

Statement-Coverage Testing for Nondeterministic Concurrent Programs

Gwan‐Hwan Hwang Heng-Yi Lin Shaoyan Lin Che-Sheng Lin

In this paper we propose a scheme for reachability testing to obtain statement coverage in the dynamic testing of concurrent programs. The proposed scheme derives inputs from SYN-sequences obtained in reachability testing and uses these inputs to perform reachability testing multiple times in order to achieve statement-coverage testing for a concurrent program.

Statement (logic)

Nondeterministic algorithm

Software testing

Code coverage

Random testing

10.1109/tase.2012.21

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Citations (4)

An efficient algorithm for computing communication sets for data parallel programs with block-cyclic distribution

Gwan‐Hwan Hwang

We present an algorithm for computing the communication sets in array section movements with block-cyclic (cyclic(k) in HPF) distribution. Our framework can handle multi-level alignments, multi-dimensional arrays, array intrinsic functions, affine indices and axis exchanges in the array subscript. Instead of employing the linear diophantine equation solver, a new algorithm which does not rely on the linear diophantine equation solver to calculate communication sets is proposed We use formal proof and experimental results to show that it is more efficient than previous solution to the same problem. Another important contribution of the paper is that we prove that the compiler is able to compute efficiently the communication sets of block-cyclic distribution as long as the block sizes of the arrays are set to be identical or the lowest common multiple (LCM) of block sizes is not a huge integer We demonstrate it by thorough complexity analyses and extensive experimental results.

Solver

10.1109/icppw.2002.1039785

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Citations (0)

A Framework for Cryptography Based Accountability and Service Invocation Control for Service Composition in a Multicloud Architecture

Trust, Security And Privacy In Computing And Communications (2015)

Gwan‐Hwan Hwang Kuh-Yih Huang Yu‐Cheng Hsiao

In this paper we address how to achieve cryptography based accountability and service invocation control in a multicloud architecture. The detection and prevention of failures for a composed service is complicated because service composition spans multiple service providers from different and independent clouds for inter-cloud collaborations. Our system supports strong accountability in which any failure or misbehavior can always be identified and associated with responsible (or guilty) entity(s) because cryptographic proofs are collected during dynamic service composing. These proofs can also be applied to service invocation control. Compared with previous work, the proposed framework does not rely on any on-line or in-line trust third party. Implementation and experimental results are presented that demonstrate the feasibility of the proposed scheme.

Invocation

10.1109/trustcom-bigdatase-ispa.2015.491

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Citations (0)

Design and Implementation of a Web-Services-Based Network File System

Gwan‐Hwan Hwang Chih-Hao Yu

Web services are Web-based enterprise applications that use open, XML-based standards and transport protocols to exchange data between calling clients and servers. In this paper, we demonstrate that Web services can be used to construct a distributed file system, called the Web-services-based network file system (WSNFS). One of the goals of the WSNFS is to provide a platform for file sharing among heterogeneous distributed file systems. Also, as the technology of Web services is widely applied to the field of grid computing, the proposed system can aid the deployment of Web services to the data grid applications. We present the architecture of the WSNFS and define the communication-protocol standard based on Web services. Our experiences in implementing the prototype as well as the experimental results demonstrate that the practicality of the WSNFS; the performance of the prototype is comparable to that of the Sun network file system.

WS-Policy

Network File System

WS-Addressing

SOAP

WS-I Basic Profile

10.1109/aict-iciw.2006.78

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Citations (0)

Proof of violation for availability in cloud systems

Gwan‐Hwan Hwang Shang-Yu Yeh

In this paper we study how to fulfill proof of violation (POV) for availability of IaaS systems in the cloud. A POV scheme enables a user or a service provider to produce a precise proof of either the occurrence of the violation of properties or the innocence of the service provider. POV schemes are solutions for obtaining mutual nonrepudiation between users and the service provider in the cloud. To the best of our knowledge, it is the first scheme that can perform availability auditing according to cryptographic proofs. Experimental results are presented that demonstrate the feasibility of the proposed scheme. Service providers can use the proposed scheme to provide a mutual nonrepudiation guarantee for availability in their service-level agreements.

Cloud service provider

Innocence

10.1109/icis.2016.7550739

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Citations (2)

Scalable and Trustworthy Cross-Enterprise WfMSs by Cloud Collaboration

Gwan‐Hwan Hwang Yi-Chan Kao Yu‐Cheng Hsiao

Establishing scalable and cross-enterprise workflow management systems (WfMSs) in the cloud requires the adaptation and extension of existing concepts for process management. This paper proposes a scalable and cross-enterprise WfMS with a multitenancy architecture. Especially, it can activate enactment of workflow processes by cloud collaboration. We do not employ the traditional engine-based WfMSs. The key idea is to have the workflow process instance to be self-protected and does not need a workflow engine to secure the data therein. Thus, the process instance discovery and activity execution can be fully independently and distributed. As a result, we can employ the data storage system, Big Table, to store the process instances, which may form a big data. The applying of element-wise encryption and chained digital signature makes it satisfy major security requirements of authentication, confidentiality, data integrity, and nonrepudiation.

10.1109/bigdata.congress.2013.19

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Citations (2)

An efficient algorithm for communication set generation of data parallel programs with block-cyclic distribution

Parallel Computing (2004)

Gwan‐Hwan Hwang

Solver

Fortran

10.1016/j.parco.2004.02.001

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Citations (5)

The Journal of Supercomputing (2003)