• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.768-770
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• 2013

We propose a symmetric key based cryptography algorithm to encode and decode the text data with limited length using 3-dimensional magic square matrix. To encode the plain text message, input text will be translated into an index of the number stored in the key matrix. Then, Caesar's shift with pre-defined constant value is fabricated to finalize an encryption algorithm. In decode process, Caesar's shift is applied first, and the generated key matrix is used with 2D magic squares to replace the index numbers in ciphertext to restore an original text.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.8
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• pp.165-170
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• 2020

As the IoT (Internet of Things) era is activated, a lot of information including personal information is being transmitted through IoT devices. For information protection, it is important to perform cryptography communication, and it is required to use a lightweight security protocol due to performance limitations. Currently, most of the encryption methods used in the security protocol use RSA and ECC (Elliptic Curve Cryptography). However, if a high performance quantum computer is developed and the Shor algorithm is used, it can no longer be used because it can easily solve the stability problems based on the previous RSA and ECC. Therefore, in this paper, we designed a security protocol that is resistant to the computational power of quantum computers. The code-based crypto ROLLO, which is undergoing the NIST (National Institute of Standards and Technology) post quantum cryptography standardization, was used, and a hash and XOR computation with low computational consumption were used for mutual communication between IoT devices. Finally, a comparative analysis and safety analysis of the proposed protocol and the existing protocol were performed.

• Journal of Advanced Information Technology and Convergence
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• v.8 no.2
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• pp.1-11
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• 2018

Multimedia contents have been increasingly available over the Internet as wireless networks systems are continuously growing popular. Unlimited access from various users has led to unauthorized access of third parties or adversaries. This paper deals with the implementation of elliptic curve cryptography (ECC) based user authentication for securing multimedia contents over the Internet. The ECC technique has been incorporated with the advanced encryption standard (AES) algorithm to ensure the complexity of the proposed authentication scheme and to guarantee authenticity of multimedia services.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.2
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• pp.41-49
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• 2016

Lossless encryption methods are more applicable than lossy encryption methods when marginal distortion is not tolerable. In this research, the author propose a novel lossless symmetric key encryption/decryption technique. In the proposed algorithm, the image is transformed into the frequency domain using the lifting wavelet transform, then the image sub-bands are encrypted in a such way that guarantees a secure, reliable, and an unbreakable form. The encryption involves scattering the distinguishable frequency data in the image using a reversible weighting factor amongst the rest of the frequencies. The algorithm is designed to shuffle and reverse the sign of each frequency in the transformed image before the image frequencies are transformed back to the pixel domain. The results show a total deviation in pixel values between the original and encrypted image. The decryption algorithm reverses the encryption process and restores the image to its original form. The proposed algorithm is evaluated using standard security and statistical methods; results show that the proposed work is resistant to most known attacks and more secure than other algorithms in the cryptography domain.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1267-1275
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• 2017

This paper describes a design of cryptographic processor supporting 233-bit elliptic curves over binary field defined by NIST. Scalar point multiplication that is core arithmetic in elliptic curve cryptography(ECC) was implemented by adopting modified Montgomery ladder algorithm, making it robust against simple power analysis attack. Point addition and point doubling operations on elliptic curve were implemented by finite field multiplication, squaring, and division operations over $GF(2^{233})$, which is based on affine coordinates. Finite field multiplier and divider were implemented by applying shift-and-add algorithm and extended Euclidean algorithm, respectively, resulting in reduced gate counts. The ECC processor was verified by FPGA implementation using Virtex5 device. The ECC processor synthesized using a 0.18 um CMOS cell library occupies 49,271 gate equivalents (GEs), and the estimated maximum clock frequency is 345 MHz. One scalar point multiplication takes 490,699 clock cycles, and the computation time is 1.4 msec at the maximum clock frequency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.2
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• pp.45-58
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• 2001

There are relatively many research results of the validation of the cryptography. But few researches on the validation of cryptography implementations were accomplished. However, developer\`s misunderstanding the crypto-algorithm or a mistake in implementation of the crypto-a1gorithm leads to lose reliability of security products. Therefore, as validation of the crypto-algorithm itself also validation of the implementation is important. The major objective of this paper is to propose Security Products Validation Tool. Our tool validates implementation of the public key algorithm (RSA. KCDSA) and hash algorithm (SHA-1, HAS-170). The validation process is composed of several items and our tool performs validation teats for conformance to related standard.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.69-75
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• 2023

Finite field arithmetic operations play an important role in a variety of applications, including modern cryptography and error correction codes. In this paper, we propose an efficient multiplication algorithm over finite fields using the Montgomery multiplication algorithm. Existing multipliers can be implemented using AND and XOR gates, but in order to reduce time and space complexity, we propose an algorithm using NAND and NOR gates. Also, based on the proposed algorithm, an efficient semi-systolic finite field multiplier with low space and low latency is proposed. The proposed multiplier has a lower area-time complexity than the existing multipliers. Compared to existing structures, the proposed multiplier over finite fields reduces space-time complexity by about 71%, 66%, and 33% compared to the multipliers of Chiou et al., Huang et al., and Kim-Jeon. As a result, our multiplier is proper for VLSI and can be successfully implemented as an essential module for various applications.

• Journal of information and communication convergence engineering
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• v.12 no.4
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• pp.237-245
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• 2014

In this study, software-based countermeasures against a side-channel cryptanalysis of the Rabbit stream cipher were developed using Moteiv's Tmote Sky, a popular wireless sensor mote based on the Berkeley TelosB, as the target platform. The countermeasures build upon previous work by improving mask generation, masking and hiding other components of the algorithm, and introducing a key refreshment scheme. Our contribution brings improvements to previous countermeasures making the implementation resistant to higher-order attacks. Four functional metrics, namely resiliency, robustness, resistance, and scalability, were used for the assessment. Finally, performance costs were measured using memory usage and execution time. In this work, it was demonstrated that although attacks can be feasibly carried out on unprotected systems, the proposed countermeasures can also be feasibly developed and deployed on resource-constrained devices, such as wireless sensors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.627-628
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• 2010

S. Chow proposes white-box cryptography mechanism of AES algorithm(WBC-AES) in 2002. WBC mechanism is implementation method which is resistant to white-box attack. We describe the WBC-AES and contents protection method using it.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.144-147
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• 2000

Data security is an important issue in today's computer networks. In order to construct a safe infra in the open communication network, a cryptography is necessarily applied to several communication application fields like a high-speed networking system supporting real-time operation. A cryptography which has already realized by a software is designed by using a hardware to improve a throughput. In this paper, we design hardware architecture of IDEA by using a single iterative round method to improve a encryption throughput. In addition, we intend to develop a hardware design methodology that a specific cryptography operate with high-speed. The hardware model is described in VHDL and synthesized by the Samsung KG 80 Library in the Synopsys development software tool. With a system clock frequency 20MHz, this hardware permits a data conversion rate of more than 116 Mbit/s.