• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.430-432
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• 2015

This paper describes a hardware implementation of ultra-lightweight block cipher algorithm PRESENT-80/128 that supports for two master key lengths of 80-bit and 128-bit. The PRESENT algorithm that is based on SPN (substitution and permutation network) consists of 31 round transformations. A round processing block of 64-bit data-path is used to process 31 rounds iteratively, and circuits for encryption and decryption are designed to share hardware resources. The PRESENT-80/128 crypto-processor designed in Verilog-HDL was verified using Virtex5 XC5VSX-95T FPGA and test system. The estimated throughput is about 550 Mbps with 275 MHz clock frequency.

• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.929-936
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• 2003

We Propose the Suity Cryptography File System to encrypt or decrypt a plaintext or an encrypted tort by using the dynamic linking mechanism In the Linux kernel. The dynamic linking mechanism gives the flexibility of the kernel without changing the kernel. The Sorority Cryptography File System uses the blowfish algorithm to encrypt or decrypt a data. To overcome the overhead of the key server, I use key generating algorithm which is installed in the same Security Cryptography File System. The Security Cryptography file System is fitted into the Linux system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.589-597
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• 2003

Visual cryptography made it possible to decrypt thresholding scheme with not digital system but human vision system. This method, however, has some limit in it. Optical visual cryptography was proposed which used laser instead of human eyesight. As a result, it was possible to adapt cryptography to optical system. However, it also had some difficulties because it did not overcome the existing problem of visual cryptography completely. These problems occurred in the process of transferring data processing system from visual to optics. Therefore, it is appropriate to approach these problems in terms of optics. This paper analyzes the level of noise and the security characteristics for optical visual cryptography in terms of frequency based on joint transform correlator.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.201-206
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• 2005

This paper designs Cryptography File System to support encrypting function. The CFS is supported in Solaris Kernel to encrypt or decrypt a plaintext or an encrypted text by using the dynamic linking mechanism. The Cryptography File System supports safe use of computer system even if an intruder gets a file by connecting with network. If he/she does not have a Cryptography File System module in the Solaris Kernel, he/she cannot read that file. The Cryptography File System was experimented into the Solaris kernel.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1023-1032
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• 2017

When a cryptographic device such as smart card performs an encryption for a plain text, an attacker can extract the secret key in it using side channel information. Especially, many researches found some weaknesses for side channel attack on the lightweight block cipher LEA designed to apply in IoT environments. In this paper, we survey several masking countermeasures to defeat the side channel attack and propose a novel masking conversion method. Even though the proposed Arithmetic-to-Boolean masking conversion method requires storage memory of 256 bytes, it can improve the LEA encryption speed up to 17 percentage compared to the case adopted the previous masking method.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.50-54
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• 2010

A Container Security Device (CSD) which is different existing RFID Tag strengthens the physical security as mounted inside the container and the information security as encrypts doubly a data. CSD must use the resources efficiently in order to operate with the battery. Therefore, it needs low-power mechanism which repeats the sleep period and channel scan period. However, by adjusting these periods, the trade-off occurs between energy efficiency and network connectivity. In this paper, we implement low-power CSD and resolve this problem by adjusting beacon period and channel scan time. As a result, We guarantee the network connectivity 95% or more and maximum life up to 16 days using common AA batteries.

• Journal of Korea Multimedia Society
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• v.17 no.10
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• pp.1182-1188
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• 2014

Recently, the research on database outsourcing has been actively done with the popularity of cloud computing. However, because users' data may contain sensitive personal information, such as health, financial and location information, the data encryption methods have attracted much interest. Existing data encryption schemes process a query without decrypting the encrypted databases in order to support user privacy protection. On the other hand, to efficiently handle the large amount of data in cloud computing, it is necessary to study the distributed index structure. However, existing index structure and query processing algorithms have a limitation that they only consider single-column query processing. In this paper, we propose a grid-based multi column indexing scheme and an encrypted query processing algorithm. In order to support multi-column query processing, the multi-dimensional index keys are generated by using a space decomposition method, i.e. grid index. To support encrypted query processing over encrypted data, we adopt the Hilbert curve when generating a index key. Finally, we prove that the proposed scheme is more efficient than existing scheme for processing the exact and range query.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.1
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• pp.65-71
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• 2017

Since existing Internet of Things(IoT) is vulnerable, it may cause property damage due to the information leakage. Especially, the smart door lock system built on the IoT can cause more damage. To solve these problems, this paper classify the data generated by the sensor according to the condition and send an alarm message to the user's smartphone through Google Cloud Message (GCM). We made it possible to check the images in real time through the smartphone application and control the door lock using the TCP / IP protocol. Also, we applied OTP-Based Matrix SEED algorithm to door lock system to improve security.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.853-856
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• 2012

모바일 디바이스의 대중화와 SNS(Social Networking Service)의 발전은 각 개인이 데이터와 정보를 생성하는 Web 2.0 의 페러다임을 앞당겼으며 최근 SNS 서비스를 통하여 새로운 형태의 커뮤니케이션 형태가 생성되었다. 이러한 커뮤니케이션 도구를 이용하는 유저는 대부분 ID 와 Password를 기반으로 사용자를 인증하여 서비스를 제공받는다. 이와 같은 서비스에서는 각 사용자의 정보자체보다 사용자의 사회적 위치와 사용자간의 관계를 이용한 보안사고가 우려된다. 근래의 ID/Password로 인증하는 방식의 웹서비스 또는 정보서비스들은 대부분 개인 PC, 스마트폰, 업무 PC 등에서 접근하는 추세이며, 임의적 장소에서 임의의 기기로 해당 서비스에 접근하는 양상은 과거에 비하여 감소하는 추세다. 이 같은 추세에 따라, 주로 사용하는 기기에 HTML5의 keygen과 Web-Storage 기능을 사용하여 암호화된 Key를 생성하고 저장하여 ID 와 Password가 노출되어도 해당 기기가 아니면 인증되지 않는 시스템을 구현 할 수 있으며 타 기기의 경우 일회성을 갖는 인증 방식을 사용하여, 기존 보다 안전한 인증 시스템을 적은 비용으로 구축 할 수 있다.

• Journal of Convergence for Information Technology
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• v.9 no.1
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• pp.142-150
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• 2019

This study is a file management security system that encrypts and decrypts computer and cloud data by using Bluetooth based cryptographic module. It is a necessary solution in terms of abuse of personal information and protection of social and national information. We developed H/W and S/W for SFMS(: Safe File Management Security) related Bluetooth module in cloud environment and implemented firmware development, encryption key generation and issuance, client program for system mobile and key management system. In the terminal internal encryption and decryption, SFMS was developed to ensure high security that the hacking itself is not possible because key values exist separately for each file.