• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.825-830
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• 2010

Generally, the copy protection mark and 2D bar-code techniques are widely used for forgery protection in printed public documents. But, it is hard to discriminate truth from the copy documents by using exisiting methods, because of that existing 2D-barcode is separated from the copy protection mark and it can be only recognized by specified optical barcord scanner. Therefor, in this paper, we proposed the forgery protection tehchnique for discriminating truth from the copy document by using watermark inserted 2D-barcord, which can be accurately distinguished not only by naked eye, but also by scanner. The copy protection mark consists of deformed patterns that are caused by the lowpass filter characteristic of digital I/O device. From these, we verified the performance of the proposed techniques by applying the histogram analysis based on the original, copy, and scanned copy image of the printed documents. Also, we suggested 2D-barcord confirmation system which can be accessed through the online server by using certification key data which is detected by web-camera, cell phone camera.

• Convergence Security Journal
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• v.23 no.1
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• pp.19-25
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• 2023

The current network environment provides a real-time interactive service from an initial one-way information prov ision service. Depending on the form of web-based information sharing, it is possible to provide various knowledge a nd services between users. However, in this web-based real-time information sharing environment, cases of damage by illegal attackers who exploit network vulnerabilities are increasing rapidly. In particular, for attackers who attempt a phishing attack, a link to the corresponding web page is induced after actively generating a forged web page to a user who needs a specific web page service. In this paper, we analyze whether users directly and actively forge a sp ecific site rather than a passive server-based detection method. For this purpose, it is possible to prevent leakage of important personal information of general users by detecting a disguised webpage of an attacker who induces illegal webpage access using traceback information

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.3
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• pp.23-40
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• 2024

Hardware attacks involve physical reverse engineering efforts to steal sensitive information, such as encryption keys and circuit designs. Encryption and obfuscation are representative countermeasures, but they are nullified if adversaries manage to find the key. To address this issue, we propose e-Cryptex, which utilizes a Physically Unclonable Function (PUF) as an anti-tampering shield. PUF acts as a random number generator and relies on unique physical variants that cannot be replicated or restored to enhance anti-tampering mechanisms. e-Cryptex uses PUF as a shield to protect the system's structure and generate the key. Tampering with the shield will result in the destruction of the key. This paper demonstrates that e-Cryptex meets PUF security requirements and is effective in detecting of tampering attempts that pierce or completely destroy the shield. Each board consistently generates the same key under normal conditions, while also showing key uniqueness across different boards.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.159-165
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• 2010

The Multi-code (Mc) modulation has been developed for high-speed data transmission over the wireless environments, but it suffers two critical problems due to the limited resource of Orthogonal Codes (OC) and high Peak-Average Power Ratio (PAPR). In this paper, we propose a novel modulation technique called AOCG [1] (Advanced Orthogonal Code Group)-OFDM (Orthogonal Frequency Division Multiplexing) to solve the above problems and obtain the variable high bit rates which can be controlled by the four parameters depending on the quality of services (QoS) required by users.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.102-106
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• 1999

In this study, inhomogeneous amplitude modulation effects on the imaging performance a lens system are expermentally investigated by measuring the diffraction OTF. The lens under the test is a binocular objective made in Korea. Inhomogeneous amplitude modulation is carried out by positioning the modulator cross contacted to the lens under test which is illuminated by collimated light beam. The aberration characteristics of the lens under test are examined by caculating the ray-fan through finite ray tracing. The MTFs of the lens illuminated by the homogeneous and inhomogeneous light beam are measured on the Gaussian image plane and compared with one another.

• Journal of Legislation Research
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• no.44
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• pp.725-756
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• 2013

In this paper, the possibility of extension of falsification conception was investigated to discuss the validity of this precedent. Consequently this extension was indispensible according to the article 237-2 of criminal code which regards the reproduced document as the document in the document crime. However, this is against the security of human right. On the contrary, there is not this kind of article in the German criminal code and the German precedents and majority theory are negative to regard it as the criminal document. And also, there is the pont of view that the reproduced document is not the criminal document because it's not the expression itself of document nominee's intention, so the article 237-2 should be demolished in Korea. According to this opinion, the serious reconsideration should be required in the legislation of this article 237-2. Nevertheless, if this extended conception is needed and it's possible, the meaning of the computer monitor's image is not able to be ignored in the conception of falsification. Therefore this should be regarded as the element of the falsification conception. In other words, this can't be evaluated as the object of falsification but the target of falsification, according to the conception extension, though the precedents do not regard it as the document in document crime.

• Information and Communications Magazine
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• v.29 no.8
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• pp.65-71
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• 2012

스마트폰을 비롯한 다양한 모바일 기기 보급이 급속도로 증가하고 있고, 이들 기기에 저장된 각종 개인정보에 대한 불법적 접근을 노라는 악성 앱들로 인한 피해가 발생하고 있다. 이들 위변조 앱 출현의 원인 중의 하나는 앱 실행화일의 역컴파일이 쉽기 때문이다. 앱 역컴파일이 쉽게 이루어지지 않도록 하기 위한 기술 중의 하나가 코드 난독화 기술이다. 따라서, 본 고에서는 일반적인 난독화 기술들을 분류하고, 현존하는 안드로이드, 아이폰, 윈도폰에 적용가능한 난독화 도구들의 기능에 대하여 조사 분석한다.

• Review of KIISC
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• v.18 no.6
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• pp.6-10
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• 2008

정보화 사회는 네트워크와 시스템에 대한 의존도가 큼에 따라 이에 대한 관리가 미흡할 경우 저장 유통되는 정보 및 자료의 위변조, 유출 등으로 인해 조직이 입는 피해는 금전적 손실뿐만 아니라 심할 경우 조직의 존립까지 위협할 수 있다. 이에 따라 정보보호의 중요성은 날로 증대하고 있으나 조직마다 다른 정보보호 접근 방법으로 인해 조직의 정보보호 수준은 차이가 심하다. 본 논문에서는 국제표준에 의한 정보보호 방법론적 요소들을 살펴보고 조직의 정보보호 수준에 영향을 미치는 요인이 무엇인지를 파악하여 조직의 정보보호 수준을 끌어올리기 위한 정책 방향 수립에 활용할 수 있도록 하고자 한다.

• The Journal of the Acoustical Society of Korea
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• v.1 no.1
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• pp.27-36
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• 1982

본 논문에서는 종래의 디지털신호 처리 방식에 비해 소형이며 광대역폭 신호를 처리할 수 있는 AE 콘빌버가 스펙트럼 확산통신 방식에서 높은 신호처리 이득과 다이나믹 레인지를 갖는 프로그램이 가능한 정합필터로 사용 될 수 있음을 실험적으로 제시하였다. 본 실험에서 사용한 AE 콘벌버는 안전 재료인 YZ-LINbO\sub 3\ 위에 중심 주파수 50MHz, 대역폭 11MHz인 SAW 지연선을 제작하고 그 위 에 저항율 50 ohm-cm인 P형 실리콘을 장착하여 구성하였으며, 이 소자는 63? PN 코드로 변조된 P나 신호를 인가하여 신호처리이득이 18dB인 프로그램이 가능한 정합필터로 사용될 수 있음을 보였다.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.393-396
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• 2010

이 시스템은 무선 주파수와 RFID 태그 사용으로 불법적인 위변조, 도��, 추적, 프라이버시 침해 등은 불가피하다. 따라서 본 논문에서는 리더와 태그 및 데이터베이스 간에 해시 체인을 이용하여 키를 생성한다. 키 정보를 전송 메시지에 추가하지 않기 때문에 공격자는 키를 획득할 수 없으며 간단한 논리 연산과 카운터만을 사용하기 때문에 저전력 RFID 시스템에 적합하다.