• Proceedings of the IEEK Conference
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• 2002.07a
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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.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.173-180
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• 2005

In this paper, we proposed the image hiding method which decreases calculation amount by encrypt partial data using discrete wavelet transform(DWT) and linear scale quantization which were adopted as the main technique for frequency transform in JPEG2000 standard. Also we used the chaotic system and cat map which has smaller calculation amount than other encryption algorithms and then dramatically decreased calculation amount. This method operates encryption process between quantization and entropy coding for preserving compression ratio of images and uses the subband selection method. Also, suggested encryption method to JPEG2000 progressive transmission. The experiments have been performed with the Proposed methods implemented in software for about 500 images. Consequently, we are sure that the proposed is efficient image encryption methods to acquire the high encryption effect with small amount of encryption. It has been shown that there exits a relation of trade-off between the execution time and the effect of the encryption. It means that the proposed methods can be selectively used according to the application areas.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.1-6
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• 2021

In this paper, an efficient implementation of AES encryption algorithm is presented for CCTV image security using C# language. In this approach, an efficient S-Box is first designed for reducing the computation time which is required in each round process of AES algorithm, and then an CCTV image security system is implemented on the basis of this algorithm on a composite field GF(((22)2)2). In addition, the shared S-Box structure is designed for realizing the minimized memory space, which is used in each round transformation and key scheduling processes. Through performance evaluation, it was confirmed that the proposed method is more efficient than the existing method. The proposed CCTV system in C# language using Visual studio 2010.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.244-251
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• 2011

We propose a new 2-step phase-shifting digital holographic optical encryption technique and analyze tolerance error for this cipher system. 2-step phase-shifting digital holograms are acquired by moving the PZT mirror with phase step of 0 or ${\pi}$/2 in the reference beam path of the Mach-Zehnder type interferometer. Digital hologram with the encrypted information is Fourier transform hologram and is recorded on CCD camera with 256 gray-level quantized intensities. The decryption performance of binary bit data and image data is analyzed by considering error factors. One of the most important errors is quantization error in detecting the digital hologram intensity on CCD. The more the number of quantization error pixels and the variation of gray-level increase, the more the number of error bits increases for decryption. Computer experiments show the results to be carried out encryption and decryption with the proposed method and the graph to analyze the tolerance of the quantization error in the system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.43-51
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• 2004

In this paper, we propose a high-level optical encryption system, which is tolerant with noises and cropping, by encrypting the phase-encoded CGH pattern of original image with the phase-encoded Fresnel diffraction pattern of random key images. For encryption, the phase-encoded CGH pattern of original image is multiplied by conjugate components which are the phase-encoded Fresnel diffraction patterns of random key images. The original information can be reconstructed by multiplying encrypted image by phase-encoded Fresnel diffraction pattern of random key images and performing Fourier transform of the multiplication result. The proposed system is robust to noises and cropping due to characteristics of CGH pattern and can guarantee high-level encryption by using Fresnel diffraction information. We verified the validity of proposed system by computer simulations, numerical analysis of noises and cropping effect and optical experiment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.183-194
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• 2004

The proliferation of the Internet and the rapid progress of wire/wireless communication technology makes security of digital images more and more important since the exchanges of digital images occur more and more frequently. And as the tight relationship between chaos theory and cryptography, many researches for development of new encryption systems based on chaotic maps have been widely progressed recently. In this paper, we propose a digital image encryption system based on both one-dimensional PLCM(Piecewise Linear Chaotic Map) and two-dimensional baker map. This proposed system is a product cipher that contains a perturbance-based chaotic stream cipher based on ID PLCM and a chaotic block cipher based on 2D baker map and is very high secure and easily implementable cipher having both a good confusion property and a good diffusion property. And with test results, we showed this system is very secure against statistical attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1477-1484
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• 2015

In this paper, a novel reversible data hiding by using Reed-Solomon (RS) code is proposed for efficient transmission in encryption image. To increase the recovery of data from encrypted image, RS codes are used to encode messages, and then the codewords can be embedded into encrypted image according to encryption key. After receiving encrypted image which embeds the codewords, the receiver firstly decryptes the encrypted image using the encryption key and get metric about codewords containing messages. According to recovery capability of RS codes, better estimation of message is done in data hiding system. Simulation results about two images and two RS codes show that the performances of the proposed schemes are better than ones of the reference scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.818-819
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• 2013

This paper propose a contents security technique for digital holographic display service. Digital holographic video system assumes the existing service frame for 2-dimensional or 3-dimensional video, which includes data acquisition, processing, transmission, reception, and reconstruction. In this paper, we perform the encryption of RGB image and depth-map for such a system. The experimental results showed that encrypting only 0.048% of the entire data was enough to hide the constants of the RGB image and depth-map.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.1
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• pp.29-35
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• 2003

In this paper, we propose an improved image decryption system using a phase-encoded image and the principle of interference. An original image and a random image consist of only binary values. The phase-encoded original image is encrypted into a binary phase-only image by multiplying with a phase-encoded random key. Therefore the phase-encoded images have two phase values 0 or $\pi$. The proposed decryption technique is simply performed by interfering between a reference wave and a direct pixel-to-pixel mapping of the encrypted image with a decrypting key. Optical experiments confirmed that the proposed technique is a simple and robust architecture for optical encryption.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.330-339
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• 2012

In this paper, we define and design the Streaming as a Service (StraaS) to support streaming service based on cloud computing. And we describe the various function and security to StraaS service. Specially, we introduce KS-MMA(Key-generation System for Multilateral Matching Authentication) and SIES(Searchable Image Encryption System) as security function for streaming service and cloud computing.