• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.713-720
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• 2008

Fingerprinting scheme uses digital watermarks to trace originator of unauthorized or pirated copies, however, multiple users may collude and escape identification by creating an average or median of their individually watermarked copies. Previous research works are based on ACC (anti-collusion code) for identifying each user, however, ACC are shown to be resilient to average and median attacks, but not to LCCA and cannot support large number of users. In this paper, we propose a practical SACC (scalable anti-collusion code) scheme and its angular decoding strategy to support a large number of users from basic ACC (anti-collusion code) with LCCA (linear combination collusion attack) robustness. To make a scalable ACC, we designed a scalable extension of ACC codebook using a Gaussian distributed random variable, and embedded the resulting fingerprint using human visual system based watermarking scheme. We experimented with standard test images for colluder identification performance, and our scheme shows good performance over average and median attacks. Our angular decoding strategy shows performance gain over previous decoding scheme on LCCA colluder set identification among large population.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.443-450
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• 2005

Digital fingerprinting is a contents-protection technique, where customer information is inserted into digital contents. Fingerprinted contents undergo various attacks. Especially, attackers can remove easily the inserted fingerprint by collusion attacks, because digital fingerprinting inserts slightly different codes according to the customers. Among collusion attacks, averaging attack is a simple, fast, and efficient attack. In this paper, we propose a video fingerprinting system that is robust to the averaging attack. In order to achieve code efficiency and robustness against the averaging attack, we adopt anti-collusion code (fingerprint code) from GD-PBIBD theory. When the number of users is increased, the size of fingerprint code also grows. Thus, this paper addresses a zero-based code modulation technique to embed and detect this fingerprint code efficiently. We implemented a blind video fingerprinting system based on our proposed technique and performed experiments on various colluding cases. Based on the results, we could detect most of colluders. In the worst case, our scheme could trace at least one colluder successfully.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1107-1110
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• 2002

본 논문에서는 현재 컨텐츠에 대한 저작권보호 기술로 활발히 연구되고 있는 워터마킹 기술과 핑거프린팅 기술에 대해 알아보고 핑거프린팅 기술의 구현시 문제시 되고 있는 공모공격의 유형을 분석한다. 워터마킹 기술은 소유권주장이 목표인 반면 핑거프린팅 기술은 사용자인증을 목표로 하는 것이 다르다. 즉, 판매되는 컨텐츠에 구매자(사용자)의 정보를 워터마크로 삽입한 후 배포하고 후에 불법복제가 의심되는 컨텐츠에 대해 적법구매자의 워터마크를 추출하여 불법재분배를 증명한다. 이는 불법복제가 어느 구매자로부터 이루어졌는지의 추적이 가능하게 한다. 하지만 핑거프린팅 기술은 워터마킹 기술과는 다르게 구매자 정보를 워터마크로 사용하기 때문에 마크가 삽입된 컨텐츠마다 서로 다르다는 특징을 갖는다. 의도적인 공격자는 이 특성을 이용하여 여러개의 핑거프린팅된 컨텐츠를 공모(collusion)하여 워터마크를 제거하기 위한 다양한 공격(attack)을 가할 수 있다. 평균화(averaging)공격과 모자익(mosaiking)공격이 공모공격의 대표적인 방법으로, 본 논문에서는 이러한 공격유형을 분석하고 공모공격에 강인한 핑거프린팅 삽입/추출방법을 고찰한다.

• Convergence Security Journal
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• v.7 no.1
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• pp.29-34
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• 2007

Recently, the distribution and using of the digital multimedia contents are easy by developing the internet application program and related technology. However, the digital signal is easily duplicated and the duplicates have the same quality compare with original digital signal. To solve this problem, there is the multimedia fingerprint which is studied for the protection of copyright. Fingerprinting scheme is a technique which supports copyright protection to track redistributers of electronic information using cryptographic techniques. Only regular user can know the inserted fingerprint data in fingerprinting schemes differ from a symmetric/asymmetric scheme and the scheme guarantee an anonymous before re-contributed data. In this paper, we present a new scheme which is the detection of colluded multimedia fingerprint by neural network. This proposed scheme is consists of the anti-collusion code generation and the neural network for the error correction.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.73-76
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• 2003

디지털 핑거프린팅은 컨텐츠 유통 시, 구매자의 정보를 컨텐츠에 삽입함으로써 불법 유통 행위된 컨텐츠에 대하여 불법 배포자를 추적할 수 있는 기법이다. 이러한 핑거프린팅 코드는 워터마크 기술로서 컨텐츠내에 삽입되어 지고, 공모 공격(collusion attacks)등과 같이 불법적인 제거 공격으로부터 삽입된 정보가 안전하게 유지되어야 한다. 본 논문에서는 효율적이고 공모 공격에 강인한 핑거프린팅 코드를 구성하고, MPSK(M-ary Phase Shift Keying) 워터마킹 기술을 이용하여 안전하게 삽입, 추출하는 알고리즘을 제안한다. 제안 방법은 다양한 영상 데이터에 적용하여 공모 공격 및 기타 영상 처리에 대한 안전성을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1839-1842
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• 2003

핑거프린팅은 컨텐츠 유통 시, 구매자의 정보를 컨텐츠에 삽입함으로써 불법 유통 행위된 컨텐츠에 대하여 불법 배포자를 추적할 수 있는 기법이다. 이 방법에는 서로 다른 구매자에 의한 핑거프린팅코드를 제거하려는 공모 공격(collusion attacks)이 발생할 수 있다. 본 논문에서는 고차의 원시다항식을 이용하여 효율적이면서 공모 공격에 강인한 핑거프린팅 코드 구성 방법을 제안한다. 그리고, 제안된 방법을 오디오 데이터에 적용하여 공모 공격에 대하여 안전한 코드임을 보이고 있다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.175-180
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• 2013

For the traitor tracing of multimedia content, this paper presents the classification algorithm of XOR collusion attack types using hamming distance, which applies to the colluded fingerprinting codes. The conventional traitor decision hinges on the colluded fingerprinting code used by a correlation coefficient, but the proposed scheme uses hamming distance. While XOR collusion attack employing a correlation coefficient is impossible to trace the traitors about 50% colluders due to a serious XOR linear problem, our method improves the performance of traceability to trace at least 1 traitor using hamming distance, and thus, the functional behavior of the proposed traitor traceability is coincided with Probability Scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.7
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• pp.41-47
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• 2011

Recently, digital contents are used a lot due to the rapid development of Internet and the commercialization of smartphones. However variety of attacks, such as collusion attack, can violate the intellectual property rights. BIBD AND-ACC is typical method to protect digital contents from attacks, but it is hard to distribute many users because of the heavy complexity of matrix computation. In this paper, we propose embedding technique to distribute BIBD AND-ACC for many users more than primitive one. We checked the PSNR result as 50.84dB when amplication factor is one and found out the colluders who involved the collusion attack by simulation.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.6
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• pp.79-86
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• 2009

In this paper, it has the performance metrics and the utility evaluation of the collusion codes about multimedia fingerprinting code based on BIBD and then the tracing algorithm of all colluders is proposed. Among the collusion codes, the bit stream of "all 0" or "all 1" are generated, also same collusion code and bit reversed code with user's fingerprinting code are generated. Thus there was occurred some problems, in which a colluder is deciding to anti-colluder or anti-colluder is deciding to colluder. In this paper, for the performance metrics and the utility evaluation of the collude codes, the experiment onto the total solution is processed by the logical collusion operation added with a partially processed averaging attack in the past papers. The proposed performance metrics and the utility evaluation about the collusion code generated from multimedia fingerprinting code based on BIBD is operated. Through the experiment, it confirmed that the ratio of colluder tracing is 100%.

• Review of KIISC
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• v.31 no.1
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• pp.57-64
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• 2021

기존의 공개키 암호가 양자 알고리즘에 취약함이 밝혀지고 양자컴퓨터의 개발이 현실화됨에 따라 NIST는 미연방표준 양자 내성 암호 공모전을 실시하고 있다. FALCON은 공모전 Round 3까지 통과한 전자서명 알고리즘으로 서명 및 검증 속도가 빠르고 공개키 및 서명 길이가 짧다는 장점이 있다. 하지만 FALCON은 부동소수점 연산 등 특별한 구조로 설계되어 새로운 형태의 부채널 공격이 존재할 수 있다. 본 논문에서는 FALCON에 대한 세 가지 전력 분석 공격의 가능성을 제시한다. 또한 주어진 공격을 활용하여 개인키를 복원하는 방안에 대해서 제시한다.