• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.11
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• pp.90-100
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• 1997

In this paper, we propose a new optical thresold generator as a key-stream genrator for stream cipher systems. The random key-bit stream is generated by a digital generator that is composed of LFSRs and nonlinear ligics. Digital implementatin of a key-stream generator requires large memory to implement programmable tapping points. This memory problem may be overcome easily by using the proposed optical system which has the proberty of 2D parallel processing.To implement hte threshold generator optically, we use conventional twisted nematic type SLMs (LCDs). This proposed system is based on the shadow casting technique for the AND operation between taps and sregister stages. It is also based on the proposed PMRS method for modulo 2 addition. The proposed PMRS method uses the property of light's polarization on LCD and can be implemented optically using one LCD and some mirrors. One of the major advantages of the proosed system is that there is no limitation of the number of the progarmmable tapping points. Therefore, the proposed system can be applied for the 2D encryption system which processes large amounts of data such as 2D images. We verify the proposed system with some simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1229-1248
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• 2016

With the feature of convenience and low cost, remote healthcare monitoring (RHM) has been extensively used in modern disease management to improve the quality of life. Due to the privacy of health data, it is of great importance to implement RHM based on a secure and dependable network. However, the network connectivity of existing RHM systems is unreliable in disaster area because of the unforeseeable damage to the communication infrastructure. To design a secure RHM system in disaster area, this paper presents a Secure VANET-Assisted Remote Healthcare Monitoring System (SVC) by utilizing the unique "store-carry-forward" transmission mode of vehicular ad hoc network (VANET). To improve the network performance, the VANET in SVC is designed to be a two-level network consisting of two kinds of vehicles. Specially, an innovative two-level key management model by mixing certificate-based cryptography and ID-based cryptography is customized to manage the trust of vehicles. In addition, the strong privacy of the health information including context privacy is taken into account in our scheme by combining searchable public-key encryption and broadcast techniques. Finally, comprehensive security and performance analysis demonstrate the scheme is secure and efficient.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2388-2404
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• 2012

Cryptographic hash functions are widely used in many information security applications like digital signatures, message authentication codes (MACs), and other forms of authentication. In response to recent advances in cryptanalysis of commonly used hash algorithms, National Institute of Standards and Technology (NIST) announced a publicly open competition for selection of new standard Secure Hash Algorithm called SHA-3. One important aspect of this competition is evaluation of hardware performances of the candidates. In this work we present efficient hardware implementations of SHA-3 finalists: JH, Keccak and Skein. We propose high speed architectures using Look-Up Table (LUT) resources on FPGAs, to minimize chip area and to reduce critical path lengths. This approach allows us to design data paths of SHA-3 finalists with minimum resources and higher clock frequencies. We implemented and investigated the performance of these candidates on modern and latest FPGA devices from Xilinx. This work serves as performance investigation of leading SHA-3 finalists on most up-to-date FPGAs.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.3
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• pp.11-20
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• 2018

Smart devices refer to various devices and control equipment such as health care devices, imaging devices, motor devices and wearable devices that use wireless network communication (e.g., Wi-fi, Bluetooth, LTE). Commercial services using such devices are found in a wide range of fields, including home networks, health care and medical services, entertainment and toys. Studies on smart devices have also been actively undertaken by academia and industry alike, as the penetration rate of smartphones grew and the technological progress made with the fourth industrial revolution bring about great convenience for users. While services offered through smart devices come with convenience, there is also various security threats that can lead to financial loss or even a loss of life in the case of terrorist attacks. As attacks that are committed through smart devices tend to pick up where attacks based on wireless internet left off, more research is needed on related security topics. As such, this paper seeks to design an access control method for reinforced security for smart devices. After registering and authenticating the smart device from the user's smart phone and service provider, a safe communication protocol is designed. Then to secure the integrity and confidentiality of the communication data, a management process such as for device renewal or cancellation is designed. Safety and security of the existing systems against attacks are also evaluated. In doing so, an improved efficiency by approximately 44% compared to the encryption processing speed of the existing system was verified.

• Journal of Sensor Science and Technology
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• v.27 no.1
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• pp.59-63
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• 2018

Among Internet of things (IoT) applications, the most demanding requirements for the widespread realization of many IoT visions are security and low power. In terms of security, IoT applications include tasks that are rarely addressed before such as secure computation, trusted sensing, and communication, privacy, and so on. These tasks ask for new and better techniques for the protection of data, software, and hardware. An integral part of hardware cryptographic primitives are secret keys and unique IDs. Physical Unclonable Functions(PUF) are a unique class of circuits that leverage the inherent variations in manufacturing process to create unique, unclonable IDs and secret keys. In this paper, we propose a low power Arbiter PUF circuit with low error rate and high reliability compared with conventional arbiter PUFs. The proposed PUF utilizes a power gating structure to save the power consumption in sleep mode, and uses a razor flip-flop to increase reliability. PUF has been designed and implemented using a FPGA and a ASIC chip (a 0.35 um technology). Experimental results show that our proposed PUF solves the metastability problem and reduce the power consumption of PUF compared to the conventional Arbiter PUF. It is expected that the proposed PUF can be used in systems required low power consumption and high reliability such as low power encryption processors and low power biomedical systems.

• Journal of Internet Computing and Services
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• v.19 no.3
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• pp.1-6
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• 2018

Widely used around the world, smartphones contain many features and can store content such as contacts, photos, and videos. Information that can be leaked in proportion to the information that the smartphone can store has also been increased. In recent years, accidents such as personal information leakage have occurred frequently. Personal information leakage is happening in the Android environment, which accounts for more than half of the smartphone operating system market share. Analyzing malicious apps that leak information can tell you how to prevent information leakage. Malicious apps that leak information will send importantinformation to the hacker's (C & C) server, which will use network communication. Malicious apps that are emerging nowadays encrypt and transmit important information through SSL communication. In this case, it is difficult to knowwhat kind of information is exposed to network. Therefore, we suggest a method to analyze malicious apps when leak important information through SSL communication. In this paper, we identify the way malicious apps leak information. And we propose a method for analyzing information leaked by SSL communication. Data before encryption was confirmed in the device through SSL hooking and SSL Strip method.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.3
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• pp.7-12
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• 2016

In a hostile Internet environment, steganography has focused to hide a secret message inside the cover medium for increasing the security. That is the complement of the encryption. This paper presents a text steganography techniques using the Hangul text. To enhance the security level, secret messages have been encrypted first through the genetic algorithm operator crossover. And then embedded into an cover text to form the stego text without changing its noticeable properties and structures. To maintain the capacity in the cover media to 3.69%, the experiments show that the size of the stego text was increased up to 14%.

• Proceedings of the CALSEC Conference
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• 2003.09a
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• pp.261-267
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• 2003

This study deals with controversial issues surrounding the today′s cyber-taxation and recommends feasible consumption tax system architecture titled Global Electronic Tax Invoice System (GETI). The GETI is an electronic consumption tax architecture to provide "all-in-one" tax and e-payment services through a trusted third party (TTP). GETI is designed to streamline the overall cyber-taxation process and provide simplified and transparent tax invoice services through an authorized np. To ensure information security, GETI incorporates public Key infrastructure (PKI) based digital certificates and other data encryption schemes when calculating, reporting, paying, and auditing tax in the electronic commerce environment. GETI is based on the OECD cyber-taxation agreement that was reached in January 2001, which established the taxation model for B2B and B2C electronic commerce transactions. For the value added tax systems, tax invoice is indispensable to commerce activities, since they provide documentations to prove the validity of commercial transactions. As paper-based tax invoice systems are gradually phased out and are replaced with electronic tax invoice systems, there is an increasing need to develop a reliable, efficient, transparent, and secured cyber-taxation architecture. To design such architecture, several desirable system attributes were considered -- reliability, efficiency, transparency, and security. GETI was developed with these system attributes in mind.

• The Journal of Korean Association of Computer Education
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• v.7 no.4
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• pp.61-66
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• 2004

Electronic commerce that use Mobile Phone according as the radio Internet develops rapidly and performance of Mobile Phone develops is activated. It is said that electronic commerce that use these Mobile Phone is M-Commerce. Also, the most important controversial point is data security or an user certification technology at these electronic commerce, there are research reactor WPKI and WTLS about this technology. However, when transmit message again after sign electronic documents in Mobile Phone, if do not encrypt, danger exists to be exposed to outside. Therefore, in this paper, designed system to encipher document that handle and handles user certification applying XML electronic sign technique in Mobile environment. Prevent of XML electronic sign in Mobile environment through this paper, and can stave off danger from outside by enciphering electronic sign document.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.499-506
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• 2003

In this paper, we propose the shift and noise tolerance method using a virtual phase image and a joint transform correlator (JTC) architecture that can alleviate the need for an accurate optical axis alignment. An encrypted image is obtained by the Fourier transform of the product of a phase- encoded virtual image to camouflage the original one and a random phase image. Therefore, even if unauthorized users analyze the encrypted image, we can prevent the possibility of counterfeiting from unauthorized people using virtual image which dose not contain any information from the original image. We demonstrate the robustness to noise, to data loss and to shift of the encrypted image using a JTC in the proposed description technique.