• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.75-84
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• 2021

In this paper, we introduce InfoDID, a robust user information management service based on DID that manages user information reliably. Since blockchain technology provides an environment in which data can be handled transparently on a decentralized basis, various services using blockchain are currently being developed As the importance of user's personal information has recently emerged, the DID technology is receiving attention. The technology allows a user to control his or her information through decentralized identifiers, and various information management services are being tried based on the technology. Using blockchain-based DID technology, InfoDID reliably controls personal information requested frequently, helping users to provide their information to other services more conveniently. In addition, to support service continuity, InfoDID uses BR2K technique that provides robust execution of blockchain application services, so that even partial service failures can be systematically recovered. To facilitate this operation, we present a replication status monitoring tool that can continuously check the replication states of blockchain application services running in association with the BR2K technique such as InfoDID.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.4
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• pp.543-552
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• 1994

This paper presents a decentralized quadratic regulation architecture with feedforward neural networks for the control problem of complex systems. In this method, the decentralized technique was used to treat several simple subsystems instead of a full complex system in order to reduce training time of neural networks, and the neural networks' nonlinear mapping ability is exploited to handle the nonlinear interaction variables between subsystems. The decentralized regulating architecture is composed of local neuro-controllers, local neuro-identifiers and an overall interaction neuro-identifier. With the interaction neuro-identifier that catches interaction characteristics, a local neuro-identifier is trained to simulate a subsystem dynamics. A local neuro-controller is trained to learn how to control the subsystem by using generalized Backprogation Through Time(BTT) algorithm. The proposed neural network based decentralized regulating scheme is applied in the power System Stabilization(PSS) control problem for an imterconnected power system, and compared with that by a conventional centralized LQ regulator for the power system.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.3
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• pp.91-98
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• 2022

With the recent increase in interest in metaverse in which virtual and physical spaces are digitally fused, many activities in physical spaces are expected to take place in web-based virtual spaces. Therefore, there is a need for research on a self-sovereign identity system that can secure privacy and mutual trust in a DID(decentralized identifier)-based virtual space environment. We, in this paper, developed and validated a reliable communication method consisting of DIDComm messages, a procedure for generating distributed identifiers, asymmetric keys, and DID documents based on Hyperledger Indy and DIDComm open sources. The developed communication method can be applied to verify each other by exchanging additional information and verifiable credentials for trust among communication participants.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.205-217
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• 2021

Decentralized SSI(Self Sovereign Identity) has become an alternative to a new digital identity solution, but an efficient de-identification technique has not been proposed due to the unique algorithmic characteristics of data transactions. In this study, to ensure the decentralized operation of SSI, we propose a de-identification technique that does not remove identifiers by restructuring the verification results of ZKP (Zero Knowledge Proof) into a form that can be provided to the outside by the verifier. In addition, it is possible to provide restructured de-identification data without the consent of data subject by proposing the concept of differential sovereignty management for each entity participating in verification. As a result, the proposed model satisfies the domestic personal information protection law in a decnetralized SSI, in addition provides secure and efficient de-identification processing and sovereignty management.

• Journal of the Korea Society of Computer and Information
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• v.26 no.6
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• pp.97-105
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• 2021

In this paper, we propose BCON, a service that allows individuals to store personal contents safely, and reliably guarantee their ownership of contents, certifying their identities with DIDs(Decentralized identifiers). DID technology, which supports decentralized identification service based on a blockchain that cannot forgery or alter data, allows users to selectively provide their information, controlling personal information and reinforcing their sovereignty over their identity. BCON stores information about the content specified by a user on the blockchain and Authenticates the user's identity based on DID technology. It also provides functions for the user to safely upload and download the user's content to a distributed database. BCON consists of the content service verifier, the content storage service, the content management contract, and the user application, administrating rhe DID registry for Authority management.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.5
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• pp.41-54
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• 2023

Smart grid that supports efficient energy production and management is used in various fields and industries. However, because of the environment in which services are provided through open networks, it is essential to resolve trust issues regarding security vulnerabilities and privacy preservation. In particular, the identification information of smart meter is managed by a centralized server, which makes it vulnerable to security attacks such as device stolen, data forgery, alteration, and deletion. To solve these problems, this paper proposes a blockchain based authentication protocol for a smart meter. The proposed scheme issues an unique decentralized identifiers (DIDs) for individual smart meter through blockchain and utilizes a random values based on physical unclonable function (PUF) to strengthen the integrity and reliability of data. In addition, we analyze the security of the proposed scheme using informal security analysis and AVISPA simulation, and show the efficiency of the proposed scheme by comparing with related work.