• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.199-200
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• 2008

In this paper, we researched optical characteristics of a holographic optical security system using a reflection recording material and optical random phase mask. The system have the property of optical security key with the phase mask. Also, a reflection recording geometry can reduced a size of the reconstruction system because a input beam to reconstruct a holographic image and a diffraction beam are the same side on the material.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.153-158
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• 2004

The security system using optical fiber is a system, circulating infrared rays laser pulse on the optical fiber which is attached on the security fence to prevent invasion, which can show invasion position with visible and audible signal on the situation monitor if an invader cut or pull the security fence with minuteness of 10m. The optical fiber can be also applied for the bed structure stability monitoring system of high speed train as well as security system. To apply this system for high speed railroad bed structures, this system will give an alarm if it detect excessive tension, shrinkage, deflection which is beyond the limit of structure, that will prevent serious railroad accident. In this paper, we like to propose that applying this system for security and structure stability can improve confidence and stability on operation of railways

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.864-867
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• 2005

All-optical networks are emerging as a promising technology for per second class communication. However, they are intrinsically different from electro-optical networks, particularly because they do not regenerate signals in the networks. The characteristics of all-optical network components and architectures manifest and still unstudied security vulnerabilities but also offer a new array of possible countermeasures. In this paper, we have analysed the security issue to protect against intrusion.

• Journal of the Optical Society of Korea
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• 제14권2호
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• pp.97-103
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• 2010

We propose a new technique for the optical encryption of gray-level optical images digitized into 8-bits binary data by ASCII encoding followed by QPSK modulation. We made an encrypted digital hologram with a security key by using 2-step phase-shifting digital holography, and the encrypted digital hologram is recorded on a CCD camera with 256 gray-level quantized intensities. With these encrypted digital holograms, the phase values are reconstructed by the same security key and are decrypted into the original gray-level optical image by demodulation and decoding. Simulation results show that the proposed method can be used for cryptosystems and security systems.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.285-285
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• 2009

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.722-732
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• 2016

A new optical one-time password (OTP) authentication method using digital holography is proposed, which enhances security strength in the authentication system. A challenge-response optical OTP algorithm based on two-factor authentication is presented using two-step phase-shifting digital holography, and two-way authentication is also performed using challenge-response handshake in both directions. Identification (ID), password (PW), and OTP are encrypted with a shared key by applying phase-shifting digital holography, and these encrypted pieces of information are verified by each party by means of the shared key. The encrypted digital holograms are obtained by Fourier-transform holography and are recorded on a CCD with 256 quantized gray-level intensities. Because the intensity pattern of such an encrypted digital hologram is distributed randomly, it guards against a replay attack and results in higher security level. The proposed method has advantages, in that it does not require a time-synchronized OTP, and can be applied to various authentication applications. Computer experiments show that the proposed method is feasible for high-security OTP authentication.

• 정보보호학회논문지
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• 제9권4호
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• pp.37-48
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• 1999

현대암호방식은 종래의 선형 대수와 수리이론을 적용한 암호통신을 벗어난 유사 잡음성을 띠는 카오스 신호를 이용한 암호통신을 적용해 오고 있다,[1-2] 본 논문은 1차 permutation 알고 리즘을 이용 하여 변환된 정보를 2차 이산 카오스 변환 함수를 이용해 암호화하는 광영상 암호시스템을 제안하여UT 다. 제안된 시스템은 키수열 발생기의 출력을 통해 영상정보를 permutation 하는 알고리즘 을 설계하였고 이에 대한 검정을 수행하였다. 또한 본 논문에서는 permutation 알고리즘을 통해 제한적인 카오스 함수 의 적용시 발생하는 문제점을 해결하고 비도를 증가시킴으로써 광영상 암호시스템에 적용 시 그 타당성 을 검정하였다. Current encryption methods have been applied to secure communication using discrete chaotic system whose output is a noise-like signal which differs from the conventional encryption methods that employ algebra and number theory[1-2] We propose an optical encryption method that transforms the primary pattern into the image pattern of discrete chaotic function first a primary pattern is encoded using permutation algorithm, In the proposed system we suggest the permutation algorithm using the output of key steam generator and its security level is analyzed. In this paper we worked out problem of the application about few discrete chaos function through a permutation algorithm and enhanced the security level. Experimental results with image signal demonstrate the proper of the implemented optical encryption system.

• Journal of the Optical Society of Korea
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• 제18권5호
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• pp.477-484
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• 2014

In this paper, we propose a new optical secret key sharing method based on the Diffie-Hellman key exchange protocol required in cipher system. The proposed method is optically implemented by using a free-space interconnected optical logic gate technique in order to process XOR logic operations in parallel. Also, we present a compact type of optical module which can perform the modified Diffie-Hellman key exchange for a cryptographic system. Schematically, the proposed optical configuration has an advantage of producing an open public key and a shared secret key simultaneously. Another advantage is that our proposed key exchange system uses a similarity to double key encryption techniques to enhance security strength. This can provide a higher security cryptosystem than the conventional Diffie-Hellman key exchange protocol due to the complexity of the shared secret key. Results of numerical simulation are presented to verify the proposed method and show the effectiveness in the modified Diffie-Hellman key exchange system.

• 전기전자학회논문지
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• 제18권3호
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• pp.328-334
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• 2014

본 논문은 OFB(Output Feedback Block) 블록 암호화 알고리즘에 대한 광학적 암호화 및 복호화 시스템을 제안한다. 제안한 방식은 암호화 과정에 필요한 XOR 논리 연산을 구현하기 위해 이중 인코딩 기법을 사용한다. 또한, 제안된 암호화 시스템은 광 병렬처리의 특성상 데이터가 2차원으로 배열되어 매우 큰 암호키를 구현할 수 있기 때문에 기존의 전자적 OFB 방식보다 한층 더 암호강도가 증강된 암호화 시스템을 제공한다. 마지막으로, 제안한 방식을 검증하기 위해 컴퓨터 시뮬레이션을 통하여 암호화 및 복호화 과정을 보여준다. 그 결과, 제안한 광학적 OFB 암호화 시스템은 광학적인 고속성과 병렬성의 이점까지 포함하기 때문에 더욱 효율적이고 강력한 광학적 블록 암호화 시스템이 가능하다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.631-634
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• 2002

In this paper, we propose an improved optical security system using three phase-encoded images and the principle of interference. This optical system based on a Mach-Zehnder interferometer consists of one phase-encoded virtual image to be encrypted and two phase-encoded images, encrypting image and decrypting image, where every pixel in the three images has a phase value of '0' and '$\pi$'. The proposed encryption is performed by the multiplication of an encrypting image and a phase-encoded virtual image which dose not contain any information from the decrypted image. Therefore, even if the unauthorized users steal and analyze the encrypted image, they cannot reconstruct the required image. This virtual image protects the original image from counterfeiting and unauthorized access.. The decryption of the original image is simply performed by interfering between a reference wave and a direct pixel-to-pixel mapping image of the encrypted image with a decrypting image. Both computer simulations and optical experiments confirmed the effectiveness of the proposed optical technique for optical security applications.