• ETRI Journal
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• v.45 no.2
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• pp.213-225
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• 2023

Physical layer security (PLS) can improve the security of both terrestrial and nonterrestrial wireless communication networks. This study proposes a simplified framework for nonterrestrial cyclic prefixed orthogonal variable spreading factor (OVSF)-encoded multiple-input and multiple-output nonorthogonal multiple access (NOMA) systems to ensure complete network security. Various useful methods are implemented, where both improved sine map and multiple parameter-weighted-type fractional Fourier transform encryption schemes are combined to investigate the effects of hybrid PLS. In addition, OVSF coding with power domain NOMA for multi-user interference reduction and peak-toaverage power ratio (PAPR) reduction is introduced. The performance of $\frac{1}{2}$-rated convolutional, turbo, and repeat and accumulate channel coding with regularized zero-forcing signal detection for forward error correction and improved bit error rate (BER) are also investigated. Simulation results ratify the pertinence of the proposed system in terms of PLS and BER performance improvement with reasonable PAPR.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.509-517
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• 2015

Side Channel Analysis of applying the power-consumption was known as effective method to analyze the key of security device based on chip. The precedential information of power-consumption was measured by the voltage distribution method using by series connection of resistor. This method was dependent on the strength of the voltage. If the voltage cannot be acquired much information which is involved with the key, the information of power-consumption significantly might be influenced by noise. If so, some of the information of power-consumption might be lost and distorted. Then, this loss can reduce the performance of the analysis. For the first time, this paper will be introduced the better way of the improvement with using the method of Current to Voltage Converter with OP-Amp. The suggested method can reduce the effect of the noise which is included in the side channel information. Therefore we can verify the result of our experiments which is provided with the improvement of the performance of side channel analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.527-536
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• 2020

It has been found that an attacker can extract the secret key embedded in a security device and recover the operation instruction using power consumption traces which are some kind of side channel information. Many profiling-based side channel attacks based on a deep learning model such as MLP(Multi-Layer Perceptron) method are recently researched. In this paper, we implemented a disassembler for operation instruction set used in the micro-controller AVR XMEGA128-D4. After measuring the template traces on each instruction, we automatically made the pre-processing process and classified the operation instruction set using a deep learning model CNN. As an experimental result, we showed that all instructions are classified with 87.5% accuracy and some core instructions used frequently in device operation are with 99.6% respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3699-3719
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• 2017

Conjunctive keyword search encryption is an important technique for protecting sensitive personal health records that are outsourced to cloud servers. It has been extensively employed for cloud storage, which is a convenient storage option that saves bandwidth and economizes computing resources. However, the process of searching outsourced data may facilitate the leakage of sensitive personal information. Thus, an efficient data search approach with high security is critical. The multi-user search function is critical for personal health records (PHRs). To solve these problems, this paper proposes a novel multi-user conjunctive keyword search scheme (mNCKS) without a secure channel against keyword guessing attacks for personal health records, which is referred to as a secure channel-free mNCKS (SCF-mNCKS). The security of this scheme is demonstrated using the Decisional Bilinear Diffie-Hellman (DBDH) and Decision Linear (D-Linear) assumptions in the standard model. Comparisons are performed to demonstrate the security advantages of the SCF-mNCKS scheme and show that it has more functions than other schemes in the case of analogous efficiency.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.13-23
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• 2017

In order to protect personal information and important information (confidential information, sales information, user information, etc.) in the internal network, companies and organizations apply encryption to the Server-To-Server or Server-To-Client communication section, And are experiencing difficulties due to the increasing number of known attacks and intelligent security attacks. In order to apply the existing S / W encryption technology, it is necessary to modify the application. In the financial sector, "Comprehensive Measures to Prevent the Recurrence of Personal Information Leakage in the Domestic Financial Sector" has been issued, and standard guidelines for financial computing security have been laid out, and it is required to expand the whole area of encryption to the internal network. In addition, even in environments such as U-Health and Smart Grid, which are based on the Internet of Things (IoT) environment, which is increasingly used, security requirements for each collection gateway and secure transmission of the transmitted and received data The requirements of the secure channel for the use of the standard are specified in the standard. Therefore, in this paper, we propose a secure encryption algorithm through mutual authentication and grouping for each node through H / W based Network Control Server (NCS) applicable to internal system and IoT environment provided by enterprises and organizations. We propose a protocol design that can set the channel.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.709-718
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• 2019

A lightweight block cipher CHAM designed for suitability in resource-constrained environment has reasonable security level and high computational performance. Since this cipher may contain intrinsic weakness on side channel attack, it should adopt a countermeasure such as masking method. In this paper, we implement the masked CHAM cipher on 32-bit microprosessor Cortex-M3 platform to resist against side channel attack and analyze their computational performance. Based on the shortcoming of having many round functions, we apply reduced masking method to the implementation of CHAM cipher. As a result, we show that the CHAM-128/128 algorithm applied reduced masking technique requires additional operations about four times.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.5080-5097
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• 2017

Channel characteristics-based secret key generation is an effective physical-layer security method. The issues of how to remove the effect of random noise and to balance the key generation rate (KGR) and the bit mismatch rate (BMR) are needed to be addressed. In this paper, to reduce the effect of random noise and extract more secret bits, a new quantization scheme with high key generation rate and low bit mismatch rate is proposed. In our proposed scheme, we try to use all measurements and correct the differences caused by noise at the boundary regions instead of simply dropping them. We evaluate and discuss the improvements of our proposed scheme. The results show that our proposed scheme achieves lower bit mismatch rate as well as remaining high key generation rate.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.561-566
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• 2013

We propose an efficient exponentiation method which is resistant against some side channel attacks in $T_2(p)$, Torus-Based-Cryptosystem. It is more efficient than the general exponentiation method in $T_2(p)$ and is resistant against SPA by using that the difference of squaring and multiplication costs is negligible. Moreover, we can randomize a message in exponentiation step using the characteristic of quotient group which naturally protects against the first DPA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.894-904
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• 1999

In this paper, a synchronized stream cryptosystem for secure communication in radio channel is designed and its security level is analyzed. The main parts of the proposed cryptosystem consist of synchronization pattern generator, session key generator, and key stream generator. The system performance is evaluated by analyzing the security level depending on the randomness, period, linear complexity, and correlation immunity. Experimental results with image data signal in the 10-1 and 10-2 channel error environment demonstrate the proper operation of the implemented crypto system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2718-2731
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• 2019

Conjunctive keyword search encryption is an important technique for protecting sensitive data that is outsourced to cloud servers. However, the process of searching outsourced data may facilitate the leakage of sensitive data. Thus, an efficient data search approach with high security is critical. To solve this problem, an efficient conjunctive keyword search scheme based on ciphertext-policy attribute-based encryption is proposed for cloud storage environment. This paper proposes an efficient mechanism for removing the secure channel and resisting off-line keyword-guessing attacks. The storage overhead and the computational complexity are regardless of the number of keywords. This scheme is proved adaptively secure based on the decisional bilinear Diffie-Hellman assumption in the standard model. Finally, the results of theoretical analysis and experimental simulation show that the proposed scheme has advantages in security, storage overhead and efficiency, and it is more suitable for practical applications.