• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.303-309
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• 2018

Internet of Things technology is an intelligent service that connects all objects to the Internet and interacts with them. It is a technology that can be used in various fields, such as device management, process management, monitoring of restricted areas for industrial systems, as well as for navigation in military theaters of operation. However, because all devices are connected to the Internet, various attacks using security vulnerabilities can cause a variety of damage, such as economic loss, personal information leaks, and risks to life from vulnerability attacks against medical services or for military purposes. Therefore, in this paper, a mutual authentication method and a key-generation and update system are applied by applying S/Key technology based on a hash chain in the communications process. A mutual authentication method is studied, which can cope with various security threats. The proposed protocol can be applied to inter-peer security communications, and we confirm it is robust against replay attacks and man-in-the-middle attacks, providing data integrity against well-known attacks in the IoT environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.4
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• pp.149-160
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• 2011

Smart Grid is the next-generation intelligent power grid that maximizes energy efficiency with the convergence of IT technologies and the existing power grid. It enables consumers to check power rates in real time for active power consumption. It also enables suppliers to measure their expected power generation load, which stabilizes the operation of the power system. However, there are high possibility that various kinds of security threats such as data exposure, data theft, and privacy invasion may occur in interactive communication with intelligent devices. Therefore, to establish a secure environment for responding to such security threat with the smart grid, the key management technique, which is the core of the development of a security mechanism, is required. Using a hash chain, this paper suggests a group key management mechanism that is efficiently applicable to the smart grid environment with its hierarchical structure, and analyzes the security and efficiency of the suggested group key management mechanism.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.105-111
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• 2017

With the emergence of the fourth industrial revolution, more and more attempts have been made to apply IoT technology to the manufacturing process and launch the product. In this paper, we propose IoT authentication scheme based on hash chain which can easily apply IoT device to small and medium enterprises in Korea. In the proposed method, the companies that installed IoT devices suitable for the manufacturing environment are selected to maintain the linkage between IoT devices so that product information and release information can be efficiently collected and managed during the entire manufacturing process. In addition, the proposed scheme is characterized in that it does not require an additional encryption / decryption algorithm because the authentication information of the IoT device is constructed based on a hash chain. As a result of the performance evaluation, the efficiency of the manufacturing process was improved by 18.5% and the processing of the manufacturing process with the IoT device was shortened by 20.1% on the average according to the application of the IoT device. In addition, the labor cost reduction costs in the manufacturing process decreased by an average of 30.7%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.6
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• pp.1413-1424
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• 2019

Cryptocurrency has limitations to be used as an actual payment method due to the scalability problem of the blockchain consensus protocol, and various off-chain solutions to solve these limitations are being studied. In this paper, we design an efficient off-chain payment channel using one-way hash function and implement the designed payment channel using Ethereum smart contract. In addition, the experiment was conducted to measure and analyze execution time and cost for each method by deploying it in the same environment as the previously implemented plasma MVP. As a result, compared with plasma MVP, the proposed solution was able to reduce the total cumulative time by about 34% and reduce the overall execution cost by about 41%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.43-55
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• 2010

${\mu}TESLA$ broadcast authentication protocol have been developed by many researchers for providing authenticated broadcasting message between receiver and sender in sensor networks. Those cause authentication delay Tree-based ${\mu}TESLA$[3] solves the problem of authentication delay. But, it has new problems from Merkel hash tree certificate structure. Such as an increase in quantity of data transmission and computation according to the number of sender or parameter of ${\mu}TESLA$ chain. ${\mu}TPCT$-based ${\mu}TESLA$[4] has an advantages, such as a fixed computation cost by altered Low-level Merkel has tree to hash chain. However, it only use the sequential values of Hash chain to authenticate ${\mu}TESLA$ parameters. So, It can't ensure the success of authentication in lossy sensor network. This paper is to propose the improved method for Tree-based ${\mu}TESLA$ by using XOR-based chain. The proposed scheme provide advantages such as a fixed computation cost with ${\mu}$TPCT-based ${\mu}TESLA$ and a message loss-tolerant with Tree-based ${\mu}TESLA$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.892-905
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• 2018

In smart home environment, certificate based signature technology is being studied by communication with Internet of Things(IoT) device. However, block - chain technology has attracted much attention because of the problems such as single - point error and management overhead of the trust server. Among them, Keyless Signature Infrastructure(KSI) provides integrity by configuring user authentication and global timestamp of distributed server into block chain by using hash-based one-time key. In this paper, we provide confidentiality by applying group key and key management based on multi - solution chain. In addition, we propose a smart home environment that can reduce the storage space by using Extended Merkle Tree and secure and efficient KSI-based authentication and communication with enhanced security strength.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.981-997
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• 2020

Blockchain technology can provide a high level security based on a decentralized distributed ledger and consensus-based structure. In order to increase the utilization of blockchain technology, it is necessary to find a way to use it in fields that require personal data processing such as health care and e-commerce. To achieve this goal, the blockchain based system should be able to comply with data privacy regulations represented by European Union(EU)'s GDPR(General Data Protection Regulation). However, because of the properties of the blockchain like the immutability and decentralized recorded data, it is difficult to technically implement the requirements of the existing privacy regulations on the blockchain. In this paper, we propose a multi-chain based access control system that can guarantee the rights of the personal data subject required by GDPR by utilizing Chameleon Hash and Attribute Based Encryption (ABE). Finally, we will show through security analysis that our system can handle personal data while maintaining confidentiality and integrity.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.99-106
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• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1188-1193
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• 2007

This paper proposes a secure data forwarding scheme on source routing-based ad-hoc networks. The scheme uses two hash-key chains generated from a trusted third party to generate Message Authentication Codes for data integrity The selected MAC keys are delivered to the ad-hoc node using a pre-shared secret between the trusted third party and a node. The proposed scheme does not require the PKI, or the provisioning of the pre-shared secrets among the ad-hoc nodes.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.293-296
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• 2007

RFID는 유비쿼터스 환경 구축에 있어 가장 큰 비중을 차지하고 있다. 하지만 이에 따른 RFID에 저장된 개인정보 유출과 이를 오남용하는 문제에 대해 많은 비판들이 쏟아져 나오고 있으며 이에 대한 보안기술에 많은 관심이 모아지고 있다. 본 논문에서는 이러한 RFID의 보안모델 중 Access Control 기존 모델과 이를 보안한 RFID 2중 Access Control 보안모델을 제안한다. 2중 Access control모델은 기존 Hash-lock Access나 Hash-chain Method모델과 비슷한 구조를 가지고 있으나 도청에 의한 키값 노출에 대한 보안성을 가지고 있으며 Tag인증에 대한 값을 계속 변화 시켜 2중으로 Access Control에 대한 인증 정보를 보안하는 구조이다.