• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.3
• /
• pp.25-32
• /
• 2019

The core of the block chain technology is solving the problem of agreement on double payment, and the PoW, PoS and DPoS algorithms used for this have been studied. PoW in-process proofs are consensus systems that require feasible efforts to prevent minor or malicious use of computing capabilities, such as sending spam e-mail or initiating denial of service (DoS) attacks. The proof of the PoS is made to solve the Nothing at stake problem as well as the energy waste of the proof of work (PoW) algorithm, and the decision of the sum of each node is decided according to the amount of money, not the calculation ability. DPoS is that a small number of authorized users maintain a trade consensus through a distributed network, whereas DPS provides consent authority to a small number of representatives, whereas PoS has consent authority to all users. If PoS is direct democracy, DPoS is indirect democracy. This study aims to contribute to the continuous development of the related field through the study of the algorithm of the block chain agreement.

• Journal of IKEEE
• /
• v.24 no.4
• /
• pp.931-941
• /
• 2020

As natural language processing technology using machine learning develops, a Smart Home Network Service (SHNS) is drawing attention again. However, it is difficult to apply a standardized authentication scheme for SHNS because of the diversity of components and the variability of users. Blockchain is proposed for data authentication in a distributed environment. But there is a limit to applying it to SHNS due to the computational overhead required when implementing a proof-of-work system. In this paper, a lightweight work proof system is proposed. The proposed lightweight proof-of-work system is proposed to manage block generation by controlling the work authority of the device. In addition, this paper proposes an access control scheme for SHNS.

• Journal of Digital Convergence
• /
• v.17 no.1
• /
• pp.195-201
• /
• 2019

This paper proposes a blockchain system to share Wireless Local Area Network (WLAN) that recently suffers from mutual interference among increasing devices using unlicensed bands. Blockchain technology can induce cooperation from users by incentivizing them with cryptocurrency like shown in Bitcoin example. In this paper, we describe Blockchain based access mechanism in WLAN instead of conventional authentication based access. Here, users can access any WLAN access point by paying through smart contract while they also receive payment from others. In order to support real-time transaction, we apply proof-of-authority that is realized by Byzantine fault tolerant protocol instead of well-known proof-of-work that requires huge computing power and delay.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.4 no.2
• /
• pp.57-66
• /
• 2008

There have been proposed various copyright protection protocols in network-based digital multimedia distribution framework. However, most of conventional copyright protection protocols are focused on the stability of copyright information embedding/extracting and the access control to data suitable for user's authority but overlooked the privacy of copyright owner and user in authentication process of copyright and access information. In this paper, we propose a solution that builds a privacy-preserving proof of copyright ownership of digital contents in conjunction with keyword search scheme. The appeal of our proposal is three-fold: (1) content providers maintain stable copyright ownership in the distribution of digital contents; (2) the proof process of digital contents ownership is very secure in the view of preserving privacy; (3) the proposed protocol is the copyright protection protocol added by indexing process but is balanced privacy and efficiency concerns for its practical use.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.29 no.6
• /
• pp.1285-1303
• /
• 2019

In the current credit scoring system, the credit bureau gathers credit information from financial institutions and calculates a credit score based on it. However, because all sensitive credit information is stored in one central authority, there are possibilities of privacy violations and successful external attacks can breach large amounts of personal information. To handle this problem, we propose privacy-preserving credit scoring in which a user gathers credit information from financial institutions, calculates a credit score and proves that the score is calculated correctly using a zero-knowledge proof and a blockchain. In addition, we propose a zero-knowledge proof scheme that can efficiently prove committed inputs to check whether the inputs of a zero-knowledge proof are actually provided by financial institutions with a blockchain. This scheme provides perfect zero-knowledge unlike Agrawal et al.'s scheme, short CRSs and proofs, and fast proof and verification. We confirmed that the proposed credit scoring can be used in the real world by implementing it and experimenting with a credit score algorithm which is similar to that of the real world.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.12
• /
• pp.6175-6189
• /
• 2019

To slove the security and efficiency problem of anonymous authentication in vehicular ad-hoc network (VANET), we adopt the bilinear pairing theory to propose an identity-based batch anonymous authentication scheme for VANET. The tamper-proof device in the on-board unit and the trusted authority jointly realize the anonymity of vehicle identity and the signature of messages, which further enhances the security of this scheme, as well as reduces the overhead of trusted authority. Batch authentication can improve the efficiency of anonymous authentication for VANET. Security and efficiency analyses demonstrate that this scheme not only satisfies such security properties as anonymity, non-forgeability and non-repudiation, but also has advantage in time and space complexity. Simulation results show that this scheme can achieve good performance in real-time VANET communication.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.13
• /
• pp.1033-1055
• /
• 2000

Almost business enterprises have recently used electronic commerce to conduct their business. Electronic commerce has come to encompass the Internet as well as EDI on private networks begun in the 1960s. The Internet is already changing the way that many companies conduct their business. Domestic electronic commerce has rapidly enhanced, while Int'l electronic commerce has gone steady. There are four issues for developing of Int'l Electronic Commerce. Firstly, The EDI Standardization is to be uniformed and prevailed over the world in UN/EDIFACT authorized by ISO. Secondly, There are two useful systems on Electronic Document Transmission, so called, Bolero project system and Trade Card System. It is thought that Bolero system will be more useful for large trading enterprises, especially, who need a Letter of Credit and electronic B/L, while T/C system is proper to small trade companies who do not need those. Successful results of Bolero system is very important for Int'l electronic commerce enterprises. Thirdly, to secure electronic signature, Int'l Certification Authority is essential for the users of Int'l electronic commerce. Trusted way of distributing public keys is to use a Int'l Certification Authority. The Int'l Certification Authority will accept user's public key, along with some proof of identity and serve as a depository of digital certificates. Both governments and the International business community must involve archiving keys with trusted third parties. Finally, It is important that all the nations and UNCITRAL continue efforts to make legal bases in Int'l electronic commerce concerned, including electronic signature, certification etc.

• International Journal of Internet, Broadcasting and Communication
• /
• v.13 no.2
• /
• pp.67-75
• /
• 2021

As pass the three revised bills, the Personal Information Protection Act was revised to have a larger application for personal information. For an industrial development through an efficient and secure usage of personal information, there is a need to revise the existing anonymity processing method. This paper modifies the Zero Knowledge Proofs algorithm among the anonymity processing methods to modify the anonymity process calculations by taking into account the reliability of the used service company. More detail, the formula of ZKP (Zero Knowledge Proof) used by ZK-SNAKE is used to modify the personal information for pseudonymization processing. The core function of the proposed algorithm is the addition of user variables and adjustment of the difficulty level according to the reliability of the data user organization and the scope of use. Through Setup_p, the additional variable γ can be selectively applied according to the reliability of the user institution, and the degree of agreement of Witness is adjusted according to the reliability of the institution entered through Prove_p. The difficulty of the verification process is adjusted by considering the reliability of the institution entered through Verify_p. SimProve, a simulator, also refers to the scope of use and the reliability of the input authority. With this suggestion, it is possible to increase reliability and security of anonymity processing and distribution of personal information.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.60
• /
• pp.257-279
• /
• 2013

Nine FTA like Korea-Chile FTA, Korea-Singapore FTA, Korea-EFTA FTA, Korea-ASEAN FTA, Korea-India CEPA, Korea-EU FTA, Korea-U.S.A. FTA, Korea-Peru FTA and Korea-Turkey have been concluded and implemented in 46 countries as of May, 2013. In addition to these nine FTA, Korea has been negotiating FTA or CEPA(Comprehensive Economic Partnership Agreement) with China and Vietnam and Indonesia. Now Korean government is about to conclude FTA agreement with Indonesia which is one of crucial trading partners in Asian countries so the objective of this paper is to suggest how to design ROO schemes properly in such upcoming FTA agreement since more activation of trade and more utilization of FTA can be depend on the details of ROO schemes. As a result, this paper suggests well-design of ROO schemes as follows ; First, self-issuance origin proof system can be considered because authority-issuance origin proof system may reduce the utilization ratio of FTA. Second, combination of indirect and direct verification system in terms of origin verification system will be more preferable because this will be more fitting to Asian countries as considering trading environments and characteristics of Asian market. Third, criteria to determine origin can be based on wholly obtained plus substantial transformation system which contains CTC plus VC along with some percentage of de minimis. In addition to this, the number of products stipulated in PSR should be minimized and applied similar manner to avoid complexity of deciding origin.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.30 no.6
• /
• pp.999-1012
• /
• 2020

As the utilize of personal health records increases in recent years, research on cryptographic protocol for protecting personal information of personal health records has been actively conducted. Currently, personal health records are commonly encrypted and outsourced to the cloud. However, this method is limited in verifying the integrity of personal health records, and there is a problem with poor data availability because it is essential to use it in decryption. To solve this problem, this paper proposes a verifiable cloud-based personal health record management scheme using Redactable signature scheme and zero-knowledge proof. Verifiable cloud-based personal health record management scheme can be used to verify the integrity of the original document while preserving privacy by deleting sensitive information by using Redactable signature scheme, and to verify that the redacted document has not been deleted or modified except for the deleted part of the original document by using the zero-knowledge proof. In addition, it is designed to increase the availability of data than the existing management schemes by designing to recover deleted parts only when necessary through the Redact Recovery Authority. And we propose a verifiable cloud-based personal health record management model using the proposed scheme, and analysed its efficiency by implementing the proposed scheme.