• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.125-134
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• 2008

A great number of RFID authentication protocols have been proposed for the secure RFID system. These are typically divided into three types according to primitive that they use : Hash-based, Re-encryption based, and XORing-based protocol. The well-known attacks in RFID system are eavesdropping. impersonating, location tracking, and so on. However, existing protocols could not provide security against above attacks, or it was not efficient to search for tags on database. Therefore, in this paper we present a protocol which is secure against above attacks by using hash function and makes Database search tags easily by attaining the state information of previous session through the shared values with all tags and database.

• Journal of KIISE
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• v.44 no.8
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• pp.860-869
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• 2017

Recently, due to the personal information security act, the encryption of personal information has attracted attention. However, if the conventional encryption scheme is used directly, the database schema must be changed because the conventional encryption scheme does not preserve the format of the data, which can yield a large cost. Therefore, the Format-Preserving Encryption(FPE) has emerged as an important technique that ensures the confidentiality of the data and maintains the database schema naturally. Accordingly, National Institute of Standards and Technology(NIST) recently published the FF1 and FF3 as standards for FPE, although problems have been found in the security of FF1 and FF3 against message recovery attacks. In this paper, we study and analyze FF1 and FF3 as the standards of FPE, as well as the message recovery attack on these schemes. We also study a secure FPE against message recovery attack and verify the efficiency by implementing standardized FF1 and FF3.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.405-415
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• 2020

With the increase in smartphone user, mobile forensics has become an essential element in modern digital forensic investigation. Mobile messenger data is very important data in mobile forensics because it can acquire information such as user's life pattern and mental state. In order to analyze messenger data, a decryption technique of an encrypted messenger data is required. Since most messengers provide a message deleting function, a technique for recovering deleted messages is required. WeChat Messenger, a messenger used by about 1 billion people around the world, uses IMEI (International Mobile Equipment Identity) information to encrypt data and provides message deletion function. In this paper, we propose a data decryption method in the absence of IMEI information and propose a method for recovering deleted messages using FTS (Full Text Search) database created for full-text search function of SQLite database.

• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1462-1471
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• 2005

Recently, the medical image has been digitized by the development of computer science and digitization of the medical devices. There are needs for database service of the medical image and long term storage because of the construction of PACS(picture archiving and communication system) following DICOM(digital imaging communications in medicine) standards, telemedicine, and et al. However, it also caused some kinds of problems, such as illegal reproduction of medical image, proprietary rights and data authentication. In this paper, we propose the new digital watermarking technique for medical image based on public key encryption algorithm for integrity verification. It prevents illegal forgery that can be caused after transmitting medical image data remotely. The watermark is the value of bit-plane in wavelet transform of the original image for certification method of integrity verification. We proposed the embedding regions are randomly chosen considering ROI, and a digital signature is made using hash function of MD5 which input is a secret key. The experimental results show that the watermark embedded by the proposed algorithm can survive successfully in image processing operations and that the watermark's invisibility is good.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.9
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• pp.243-250
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• 2021

Recently, with the development of cloud computing, interest in database outsourcing is increasing. However, when the database is outsourced, there is a problem in that the information of the data owner is exposed to internal and external attackers. Therefore, in this paper, we propose a parallel range query processing algorithm that supports privacy protection. The proposed algorithm uses the Paillier encryption system to support data protection, query protection, and access pattern protection. To reduce the operation cost of a checking protocol (SRO) for overlapping regions in the existing algorithm, the efficiency of the SRO protocol is improved through a garbled circuit. The proposed parallel range query processing algorithm is largely composed of two steps. It consists of a parallel kd-tree search step that searches the kd-tree in parallel and safely extracts the data of the leaf node including the query, and a parallel data search step through multiple threads for retrieving the data included in the query area. On the other hand, the proposed algorithm provides high query processing performance through parallelization of secure protocols and index search. We show that the performance of the proposed parallel range query processing algorithm increases in proportion to the number of threads and the proposed algorithm shows performance improvement by about 5 times compared with the existing algorithm.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.1-10
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• 2014

Through the development of internet mobile devices and online business activation, sensitive data of unspecified user is being easily exposed. In such an open business environment, the outflow of sensitive personal information has often been remarked on recently for which adoption of encryption solution for database became top priority in terms of importance. In 2011, government also legislated for the protection of personal information as an information network law, and is now applying the law to a variety of industries. Firms began to comply with these regulations by establishing various measures for protection of personal information and are now quickly introducing encryption solution to reinforce security of personal information they are managing. In this paper, I present architecture and technological parts that should be considered when introducing security solution.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.69-80
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• 2007

To protect personal information when releasing data, a general privacy-protecting technique is the removal of all the explicit identifiers, such as names and social security numbers. De-identifying data, however, provides no guarantee of anonymity because released information can be linked to publicly available information to identify them and to infer information that was not intended for release. In recent years, two emerging concepts in personal information protection are k-anonymity and $\ell$-diversity, which guarantees privacy against homogeneity and background knowledge attacks. While these solutions are signigicant in static data environment, they are insufficient in dynamic environments because of vulnerability to inference. Specially, the problem appeared in record deletion is to deconstruct the k-anonymity and $\ell$-diversity. In this paper, we present an approach to securely anonymizing a continuously changeable dataset in an efficient manner while assuring high data quality.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.38-47
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• 2021

This study is about a blockchain-based collective quarantine management system and its commercialization model. The configuration of this system includes a biometric information transmission unit that generates biometric information based on measured values generated from wearable devices, a biometric information transmission unit that transmits biometric information generated here from a quarantine management platform, and action information transmitted from the community server. is a system including an action information receiving unit for receiving from the quarantine management platform. In addition, a biometric information receiving unit that collects biometric information from the terminal, an encryption unit that encodes biometric information generated through the biometric information receiving unit based on blockchain encryption technology, and a database of symptoms of infectious diseases to store symptom information and an infection diagnosis database. The generated database includes a location information check unit that receives from the terminal of the user identified as a symptomatic person and determines whether the user has arrived in the community based on the location information confirmation unit and the location of the user after the location is confirmed. It includes a community arrival judgment unit that judges. And, the community server helps the interaction between the generated information. Such a blockchain based collective quarantine management system can help to advance the existing quarantine management system and realize a safer and healthier society.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.197-205
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• 2015

Existing Web authentication method utilizes the resident registration number by credit rating agencies separating i-PIN authentication method which has been improved authentication using resident registration number via the real name confirmation database. By improving the existing authentication method, and it provides the available integrated ID authentication on Web. In order to enhance safety, the proposed authentication method by encrypting the user of the verification value, and stores the unique identifier in the database of the certificate authority. Then, the password required to log in to the Web is for receiving a disposable random from the certificate authority, the user does not need to remember a separate password and receives the random number by using the smart phone. It does not save the user's personal information in the database, and it is easy to management of personal information. Only the integration ID needs to be remembered with random number on every time. It doesn't need to use various IDs and passwords if you use this proposed authentication methods.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.34-36
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• 2005

RFID는 IC칩에 내장된 정보를 무선주파수를 이용하여 비접촉방식으로 읽는 기술로서 유비쿼터스 시대를 맞이하여 주목받는 기술이다. 그러나 사용자도 알지 못하는 사이에 리더가 요구하는 질의에 자동으로 응답하는 RFID 태그의 특성은 사용자의 개인 정보 노출의 위험이 있다. 본 논문에서는 이러한 RFID 시스템의 문제점을 해결하기 위한 기존의 방법을 알아보고, 문제점을 분석한다. 또한 해쉬 함수를 이용하여 암호화하고, 리더 ID를 사용하여 데이터베이스와 리더간의 인증을 보완한 안전한 RFID 인증 프로토콜을 제안하고 설명한다.