• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.123-132
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• 2015

In cloud storage, processing the duplicated data, namely deduplication, is necessary technology to save storage space. Users who store sensitive data in remote storage want data be encrypted. However Cloud storage server do not detect duplication of conventionally encrypted data. To solve this problem, Convergent Encryption has been proposed. But it inherently have weakness due to brute-force attack. On the other hand, to save storage space as well as save bandwidths, client-side deduplication have been applied. Recently, various client-side deduplication technology has been proposed. However, this propositions still cannot solve the security problem. In this paper, we suggest a secure source-based deduplication technology, which encrypt data to ensure the confidentiality of sensitive data and apply proofs of ownership protocol to control access to the data, from curious cloud server and malicious user.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.781-787
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• 2007

Network Mobility (NEMO) basic support protocol doesn't execute the process of route optimization and has not presented the particular security mechanism in other blocks except hi-directional tunnel between Mobile Router (MR) and its Home Agent (HA). Therefore in this paper we process secure route optimization courses through authenticated binding update protocol between MR and its Correspondent Node (CN) and the protocol of the competency of mandate between MR and its Mobile Network Node (MNN); its block also uses an bi-directional tunnel as the block between MR and its HA. The address of each node are generated by the way of Cryptographically Generated Address (CGA) for proving the ownership of address. Finally we analyze the robustness of proposed protocol using security requirements of MIPv6 and existing attacks and the efficiency of this protocol using the connectivity recovery and end-to-end packet transmission delay time.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.122-128
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• 2015

As multimedia information is spread over cyber networks, problems such as protection of legal rights and original proof of an information owner raise recently. Various image transformations of DCT, DFT and DWT have been used to embed a watermark as a token of ownership. Recently, SVD being used in the field of numerical analysis is additionally applied to the watermarking methods. A watermarking method is proposed in this paper using Gabor cosine and sine transform as well as SVD for embedding and extraction of watermarks for digital images. After delivering attacks such as noise addition, space transformation, filtering and compression on watermarked images, watermark extraction algorithm is performed using the proposed GCST-SVD method. Normalized correlation values are calculated to measure the similarity between embedded watermark and extracted one as the index of watermark performance. Also visual inspection for the extracted watermark images has been done. Watermark images are inserted into the lowest vertical ac frequency band. From the experimental results, the proposed watermarking method using the singular vectors of SVD shows large correlation values of 0.9 or more and visual features of an embedded watermark for various attacks.

• Journal of Science and Technology Studies
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• v.19 no.2
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• pp.207-249
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• 2019

This study aims to show the dynamics behind official historical descriptions, tracking the development of information system for Seoul Olympic Games. Shortly after the decision was made to host the Seoul Olympics, the South Korean government planned to import a computer system used in the previous Olympics. In response, scientists at Electronic Data Processing Center of KAIST put much effort into persuading the authorities to take the initiative in their own development, and they had to prove their capabilities by developing a computer system that worked safely in the National Sports Festival. With the development of the Olympic information system taking shape, various disputes arose among the host ministries, participating organizations and researchers. As a result, the end product resulted in a modularity of four different systems developed by different agencies, rather than a single system. For this reason, no organization claimed ownership or directly inherited the technical performance of the Olympic computer system, although it was praised as a "gold medal outside the arena." Nevertheless, the technology, hardware and manpower accumulated during the development process have since spread to various areas, laying the groundwork for the development of South Korea's information and communication technology.

• Journal of Industrial Convergence
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• v.20 no.9
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• pp.47-58
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• 2022

Digital content is difficult to distinguish between the original and the replica due to its nature. For this reason, NFT technology using blockchain technology is attracting attention because it can guarantee the proof and scarcity of the original digital content. However, the NFT buyer does not own the copyright to the digital content, but the ownership. In particular, since the minting process of issuing NFTs is possible for anyone, there is a copyright threat to the copyright holder. In this study, we propose a verification protocol based on DID for the process of issuing and transacting NFTs for copyright protection of copyright holders' digital contents. As a research method, the problems of research cases related to digital contents were analyzed and the safety was comparatively analyzed. NFT issuance can only be issued by copyright holders whose identity has been verified through DID, and only users who have completed authentication can participate in the transaction to prevent indiscriminate theft and use of digital content and form a safe and transparent transaction market.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.75-82
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• 2009

The comparison of images uses PSNR generally. In the case that PSNR value is above 35, it is hard to distinguish the quality of images. In 2006 Lee has proposed the protocol to be able to prove ownership of image using publishing MSB bit strings of original image instead of original images and used the new function to measure correlation of MSB bit strings of two images. In the view of measuring the quality of images, correlation is a bit different from PSNR. That is, if an object image to gene ate from an original image has lower quality, PSNR has very low value, but though the quality is bad, correlation of the images is very high in the view of similarity. In this paper, we modify MSB comparison function that LEE suggested and propose the ICOR function, then analyze the possibility to decide correlation of two images.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.11
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• pp.403-410
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• 2022

Non-Fungible Tokens (NFTs) created on the basis of blockchain have their own unique value, so they cannot be forged or exchanged with other tokens or coins. Using these characteristics, NFTs can be issued to digital assets such as images, videos, artworks, game characters, and items to claim ownership of digital assets among many users and objects in cyberspace, as well as proving the original. However, interest in NFTs exploded from the beginning of 2020, causing a lot of load on the blockchain network, and as a result, users are experiencing problems such as delays in computational processing or very large fees in the mining process. Additionally, all actions of users are stored in the blockchain, and digital assets are stored in a blockchain-based distributed file storage system, which may unnecessarily expose the personal information of users who do not want to identify themselves on the Internet. In this paper, we propose an NFT platform using cloud computing, access gate, conversion table, and cloud ID to improve usability and privacy problems that occur in existing system. For performance comparison between local and cloud systems, we measured the gas used for smart contract deployment and NFT-issued transaction. As a result, even though the cloud system used the same experimental environment and parameters, it saved about 3.75% of gas for smart contract deployment and about 4.6% for NFT-generated transaction, confirming that the cloud system can handle computations more efficiently than the local system.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.9
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• pp.419-430
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• 2023

Currently, NFTs have no dominant application except for the proof of ownership for digital content, and it also have small liquidity problem, which makes their price difficult to predict. Real estate usually has very high barriers to investment due to its high pricing. Real estate can be converted into NFTs and also divided into small value fungible tokens (FTs), and it can increase the the volume of the investor community due to more liquidity and better accessibility. In this document, we implement and design a system that allows ordinary users can invest on high priced real estate utilizing Black Litterman (BL) model-based Portfolio investment interface. To this end, we target a set of real estates pegged as collateral and issue NFT for the collateral using blockchain. We use oracle to get the current real estate information and to monitor varying real estate prices. After tokenizing real estate into NFTs, we divide the NFTs into easily accessible price FTs, thereby, we can lower prices and provide large liquidity with price volatility limited. In addition, we also implemented BL based asset portfolio interface for effective portfolio composition for investing in multiple of real estates with small investments. Using BL model, investors can fix the asset portfolio. We implemented the whole system using Solidity smart contracts on Flask web framework with public data portals as oracle interfaces.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.63-101
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• 2020

'Flight safety zone' means a zone that the Minister of National Defense designates under Articles 4 and 6 of the Protection of Military Bases and Installations Act (hereinafter 'PMBIA') for the safety of flight during takeoff and landing of military aircrafts. The purpose of flight safety zone is to contribute to the national security by providing necessary measures for the protection of military bases and installations and smooth conduct of military operations. In this case, when the state set and used the flight safety zone, the landowner claimed restitution of unjust enrichment against the country. This article is an analysis based on the existing legal theory regarding the legitimacy of plaintiff's claim, and the summary of the discussion is as follows. A person who without any legal ground derives a benefit from the property or services of another and thereby causes loss to the latter shall be bound to return such benefit (Article 741 of the Civil Act). Since the subject matter is an infringing profit, the defendant must prove that he has a legitimate right to retain the profit. The State reserves the right to use over the land designated as a flight safety zone in accordance with legitimate procedures established by the PMBIA for the safe takeoff and landing of military aircrafts. Therefore, it cannot be said that the State gained an unjust enrichment equivalent to the rent over the land without legal cause. Expropriation, use or restriction of private property from public necessity and compensation therefor shall be governed by Act: provided, that in such a case, just compensation shall be paid (Article 23 (1) of the Constitution of The Republic of KOREA). Since there is not any provision in the PMBIA for loss compensation for the case where a flight safety zone is set over land as in this case, next question would be whether or not it is unconstitutional. Even if it is designated as a flight safety zone and the use and profits of the land are limited, the justification of the purpose of the flight safety zone system, the appropriateness of the means, the minimization of infringement, and the balance of legal interests are still recognized; thus just not having any loss compensation clause does not make the act unconstitutional. In conclusion, plaintiff's claim for loss compensation based on the 'Act on Acquisition of and Compensation for land, etc. for Public Works Projects', which has no provision for loss compensation due to public limits, is unjust.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.45-79
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• 2018

An increase of airplanes and military aircraft operation lead to significant demanding of residential claims by people who live in nearby airports and military bases due to noise, vibration and residential damages caused by aircraft operations. In recent years, a plaintiff has filed a lawsuit against the defendant, claiming the prohibition of using claimant's possessed land as a helicopter landing route, and the Daejeon High Court was in favour of the plaintiff. Although the Supreme Court later dismissed the Appeal Court decision, it is necessary to discuss the case of setting flight prohibited zone. In Japan, the airport noise lawsuits have been filed for a long time, mainly by environmental groups. Unlike the case that admitted residential damages caused by noise, the Yokohama District Court for the first time sentenced a judgment of the prohibition of the flight. This ruling was partially changed in the appellate court and some of the plaintiffs' claims were adopted. However, the Supreme Court of Japan finally rejected such decision from appeal and district courts. Atsugi Base is an army camp jointly used by the United States and Japan, and residents, live nearby, claim that they are suffering from mental damage such as physical abnormal, insomnia, and life disturbance because of the noise from airplane taking off and landing in the base. An administrative lawsuit was therefore preceded in the Yokohama District Court. The plaintiff requested the Japan Self-Defense Forces(hereinafter 'JSDF') and US military aircraft to be prohibited operating. The court firstly held the limitation of the flight operation from 10pm to 6am, except unavoidable circumstance. The case was appealed. The Supreme Court of Japan dismissed the original judgment on the flight claim of the JSDF aircraft, canceled the first judgment, and rejected the claims of the plaintiffs. The Supreme Court ruled that the exercise of the authority of the Minister of Defense is reasonable since the JSDF aircraft is operating public flight high zone. The court agreed that noise pollution is such an issue for the residents but there are countermeasures which can be taken by concerned parties. In Korea, the residents can sue against the United States or the Republic of Korea or the Ministry of National Defense for the prohibition of the aircraft operation. However, if they claim against US government regarding to the US military flight operation, the Korean court must issue a dismissal order as its jurisdiction exemption. According to the current case law, the Korean courts do not allow a claimant to appeal for the performance of obligation or an anonymous appeal against the Minister of National Defense for prohibiting flight of military aircraft. However, if the Administrative Appeals Act is amended and obligatory performance litigation is introduced, the claim to the Minister of National Defense can be permitted. In order to judge administrative case of the military aircraft operation, trade-off between interests of the residents and difficulties of the third parties should be measured in the court, if the Act is changed and such claims are granted. In this connection, the Minister of National Defense ought to prove and illuminate the profit from the military aircraft operation and it should be significantly greater than the benefits which neighboring residents will get from the prohibiting flight of military aircraft.