• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.373-380
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• 2007

In this paper we propose a new efficient authentication protocol that reduces overheads of computation for digital signature generation/verification on mobile devices in the Personal Area Network (PAN). In particular, we focus on eliminating the traditional public key operations on mobile devices without any assistance of a signature server. Moreover, the proposed protocol provides a simplified procedure for certificate status management to alleviate communication and computational costs on mobile devices in the PAN.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1233-1236
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• 2005

Mobile IP 는 모바일 노드(MN)의 이동성을 지원하기 위한 프로토콜로, 등록 프로토콜을 통해 이동 중에도 지속적인 서비스를 제공받게 된다. 등록 프로토콜은 무선 환경에서 다양한 MN 을 대상으로 수행되기 때문에, 반드시 인증절차가 필요하며, 인증을 위한 키 관리를 위해 AAA 를 도입하는 것이 일반적인 접근방식이다. 본 논문에서는 AAA 도입한 기본적인 Mobile IP 모델에 본 논문에서 새롭게 제안하는 계층적 키 관리기법을 도입하고, AAA 지연을 최소화하는 효율적이고 안전한 등록 프로토콜을 제안한다. 또한 제안 프로토콜은 해쉬체인을 이용하여 차후 MN 의 네트워크 서비스 사용에 대한 부인방지 서비스도 제공된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.633-641
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• 2008

Since WSNs encounter attacks, such as jamming or eavesdropping without physical access occurs, security is one of the important requirements for WSNs. The key pre-distribution scheme that was recently researched for advance of security in WSNs distributes the keys and probability with the use of q-composite random key pre-distribution method, but there is a high probability that no key shared between sensor nodes, and it takes a lot of time and energy to find out the shared key. Therefore, it is not suitable for WSNs. In order to enhance stability of a node that plays a role of gateway without depending on probabilistic key, this paper proposesa key pre-distribution scheme combined with random key pre-distribution scheme and double hash chain. Since the proposed scheme can maintain a small storage place and strong security strengths, it is more efficient than the existing schemes with the same security strengths. In addition, since it uses a small size of key generation key set, it can reduce a great deal of storage overhead.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.77-82
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• 2018

Recently, as cloud services become popular with general users, users' information is freely transmitted and received among the information used in the cloud environment, so security problems related to user information disclosure are occurring. we propose a method to secure personal information of multiple users by making personal information stored in the cloud server and a key for accessing the shared information so that the privacy information of the multi users using the cloud service can be prevented in advance do. The first key used in the proposed scheme is a key for accessing the user 's personal information, and is used to operate the information related to the personal information in the form of a multi - layer. The second key is the key to accessing information that is open to other users than to personal information, and is necessary to associate with other users of the cloud. The proposed scheme is constructed to anonymize personal information with multiple hash chains to process multiple kinds of information used in the cloud environment. As a result of the performance evaluation, the proposed method works by allowing third parties to safely access and process the personal information of multiple users processed by the multi - type structure, resulting in a reduction of the personal information management cost by 13.4%. The efficiency of the proposed method is 19.5% higher than that of the existing method.

• Smart Media Journal
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• v.9 no.4
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• pp.91-96
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• 2020

A blockchain is a technology in which all nodes participating in a distributed network manage each transaction's contents without a central server managing the transaction, which is a record of the transaction. The block containing the transaction record of a specific period is connected to the blockchain by referring to the hash value for the previous block, and the chain with the new block added is shared with all nodes again. Transactions using existing certificates will pass through FinTech, and in the near future, applications using blockchains are expected to emerge. In this study, we analyze the problems of the existing model, and propose a transaction model that applies the blockchain to come. Among various applications, this study develops a trading model targeting the energy sales market among the topics that will lead the fourth industrial revolution. As a result of analyzing the proposed model, it was possible to be sure of the possibility of a safer energy sales transaction than the existing method.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.345-347
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• 1999

Payword 프로토콜은 전체적인 프로토콜의 수행 과정이 복잡하지 않고, 과도한 암호화 모듈을 사용하는 대신 단방향 해쉬 함수를 사용함으로써 전체 시스템의 속도가 빠르며, 대금을 지불하고 정산하는 방식에 있어 상당항 효율성을 가지고 있어 소액대금결제시스템으로 안성맞춤이다. 그러나 Payword 프로토콜은 프로토콜의 구조적인 결함으로 생길 수 있는 문제점을 가지고 있다. Payword 프로토콜에서 사용자는 상거래 행위에 참가하기 위해 Broker에게 계좌요구정보를 전송한 후, 그 결과로 Certificate를 받는다. 사용자는 전송 받은 Certificate를 기반으로 Commitment를 생성하고 이를 Vendor에 전송한다. Vendormss Commitment에 기반으로 하여 일정 기간동안의 사용자의 Payword 체인은 정당한 것으로 간주함으로 상거래 행위가 생긴다. 따라서 매우 빠르고 효율적인 상거래 행위가 진행될 수 있다. 그러나 사용자는 여러 Vendord와 거래하기 위해서는 Commitment를 각각의 Vendor에 전송하여야 한다. 이점을 악용하여 사용자는 자신이 Broker와 사용하기로 약정한 Payword 체인을 여러 Vendor에서 전부 사용할 수 있는 문제가 발생하게 된다. 본 논문에서는 이러한 사용자에 의한 악의적인 Payword의 사용을 방지하고, 보다 소액대금결제 시스템에 적합한 Payword 프로토콜을 개정한 Payword 프로토콜을 제안한다.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.121-128
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• 2021

After entering the 4th Industrial Revolution, the digital content market, which was only dependent on existing contents supply enterprises, is providing various digital content through the participation of users like YouTube. Accordingly, it activated the digital content market, but it causes a negative influence on the digital content market due to the copyright of the creator and the indiscriminate illegal use and usage of the content. This study researched digital content management technology based on blockchain technology to protect digital content and the copyright of the creator. The suggested technology protects the digital content and the copyright holder and discerns the users and prevents the indiscriminate approach and illegal use of digital content. For the safe management of digital content, hash function applied as the certification technology of blockchain is used to certify the users and manage the digital content and provide integrity and authentication service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1407-1417
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• 2009

We propose a e-document management system that can provide segmented page information on a document according to different levels of authority from access control environment. The proposed system creates hierarchy identifier using a one-way hash chain and therefore does not need to own key information for all users as in existing system. Also by creating group keys by compounding hash chain hierarchy identifier with randomly formed group identifier, the system can flexibly respond to dynamic changes from group member movements while at the same time resolving the problems of key formation and management in document encoding technique using symmetric key for each page. Lastly as a result of comparative analysis through an experiment with existing e-document management systems, the proposed system showed superiority in the efficiency of encoding and decoding document and the speed of encoding and decoding by the pages.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.5
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• pp.831-847
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• 2013

The various types of data are being created in large quantities resulting from the spread of social media and the mobile popularization. Many companies want to obtain valuable business information through the analysis of these large data. As a result, it is a trend to integrate the big data technologies into the company work. Especially, Hadoop is regarded as the most representative big data technology due to its terabytes of storage capacity, inexpensive construction cost, and fast data processing speed. However, the authentication token system of Hadoop Distributed File System(HDFS) for the user authentication is currently vulnerable to the replay attack and the datanode hacking attack. This can cause that the company secrets or the personal information of customers on HDFS are exposed. In this paper, we analyze the possible security threats to HDFS when tokens or datanodes are exposed to the attackers. Finally, we propose the secure authentication protocol in HDFS based on hash chain.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.11
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• pp.495-502
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• 2013

In this paper, we present an anonymous authentication and location assurance protocol for secure location-aware services over vehicular ad hoc networks (VANETs). In other to achieve our goal, we propose the notion of a location-aware signing key so as to strongly bind geographic location information to cryptographic function while providing conditional privacy preservation which is a desirable property for secure vehicular communications. Furthermore, the proposed protocol provides an efficient procedure based on hash chain technique for revocation checking to effectively alleviate communication and computational costs on vehicles in VANETs. Finally, we demonstrate comprehensive analysis to confirm the fulfillment of the security objectives, and the efficiency and effectiveness of the proposed protocol.