• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.135-140
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• 2004

In Crypto 2002 May analyzed the relation between the size of two primes and private key in unbalanced RSA with small CRT exponent. Also in Crypto 2003 he showed that if $N^{1}$4/ amount of most significant bits(least significant bits) of $d_{p}$ is exposed in balanced RSA with CRT, N can be factored. To prove this he used Howgrave-Graham's Theorem. In this paper we show that if $N^{1}$4/ amount of $d_{p}$ , p is smaller than q, and bigger than $N^{0.382}$ to avoid May's attack, is exposed in unbalanced RSA with small CRT exponent, it is enough to expose $d_{p}$ . We use Coppersmith's theorem with unbalanced primes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.17-25
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• 2008

The differential power attack (DPA)[8] is a very powerful side-channel attack tool against various cryptosystems and the masking method[10] is known to be one of its algorithmic countermeasures. But it is non-trivial to apply the masking method to non-linear functions, especially, to arithmetic adders. This paper proposes simple and efficient masking methods applicable to arithmetic adders. For this purpose, we use the fact that every combinational logic circuit (including the adders) can be decomposed into basic logic gates (AND, OR, NAND, NOR, XOR, XNOR, NOT) and try to devise efficient masking circuits for these basic gates. The resulting circuits are then applied to the arithmetic adders to get their masking algorithm. As applications, we applied the proposed masking methods to SEED and SHA-1 in hardware.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.327-336
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• 2012

In this paper, we propose user authentication methods using a microphone and a speaker in smart phones. The proposed methods guarantee that the user is located close to the target device by transmitting the challenge via an audio channel. We propose two authentication methods; user authentication for a PC or a website using a smart phone as a hardware token, and user authentication to log on to a smart phone using a PC as a token. Because our methods use typical peripheral devices such as a microphone and a speaker, they do not require any special-purpose hardware equipment. In addition, the elderly and the handicapped can easily use our methods because the methods are activated by simple operations.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.23-28
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• 2021

The article discusses the features of adaptation of the parameters of the physical layer of data transmission in self-organizing networks based on unmanned aerial vehicles operating in the conditions of "smart cities". The concept of cities of this type is defined, the historical path of formation, the current state and prospects for further development in the aspect of transition to "smart cities" of the third generation are shown. Cities of this type are aimed at providing more comfortable and safe living conditions for citizens and autonomous automated work of all components of the urban economy. The perspective of the development of urban mobile automated technical means of infocommunications is shown, one of the leading directions of which is the creation and active use of wireless self-organizing networks based on unmanned aerial vehicles. The advantages of using small-sized unmanned aerial vehicles for organizing networks of this type are considered, as well as the range of tasks to be solved in the conditions of modern "smart cities". It is shown that for the transition to self-organizing networks in the conditions of "smart cities" of the third generation, it is necessary to ensure the adaptation of various levels of OSI network models to dynamically changing operating conditions, which is especially important for the physical layer. To maintain an acceptable level of the value of the bit error probability when transmitting command and telemetry data, it is proposed to adaptively change the coding rate depending on the signal-to-noise ratio at the receiver input (or on the number of channel decoder errors), and when transmitting payload data, it is also proposed to adaptively change the coding rate together with the choice of modulation methods that differ in energy and spectral efficiency. As options for the practical implementation of these solutions, it is proposed to use an approach based on the principles of neuro-fuzzy control, for which examples of determining the boundaries of theoretically achievable efficiency are given.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.965-973
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• 2022

As IoT(Internet of Things) devices become common, many algorithms have been developed to protect users' personal information. The laser fault injection attack that threatens those algorithms is a side-channel analysis that intentionally injects a laser beam to the outside of a device to acquire confidential information or abnormal privileges of the system. There are many studies to determine the timing of fault injection to reduce the number of necessary fault injections, but the location to inject faults is only repeatedly searched for the entire area of the device. However, when fault injection is performed in an algorithm-independent area, the attacker cannot obtain the intended faulted statement or attempt to bypass authentication, so finding areas vulnerable to fault injection and performing an attack is an important consideration in achieving a high attack success rate. In this paper, we show that a 100% attack success rate can be achieved by determining the vulnerable areas for fault injection by using electromagnetic and thermal information generated from the device's chip. Based on this, we propose an efficient fault injection attack system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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• pp.1051-1077
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• 2021

The secure communication of information is a major concern over the internet. The information must be protected before transmitting over a communication channel to avoid security violations. In this paper, a new hybrid method called compressed encrypted data embedding (CEDE) is proposed. In CEDE, the secret information is first compressed with Lempel Ziv Welch (LZW) compression algorithm. Then, the compressed secret information is encrypted using the Advanced Encryption Standard (AES) symmetric block cipher. In the last step, the encrypted information is embedded into an image of size 512 × 512 pixels by using image steganography. In the steganographic technique, the compressed and encrypted secret data bits are divided into pairs of two bits and pixels of the cover image are also arranged in four pairs. The four pairs of secret data are compared with the respective four pairs of each cover pixel which leads to sixteen possibilities of matching in between secret data pairs and pairs of cover pixels. The least significant bits (LSBs) of current and imminent pixels are modified according to the matching case number. The proposed technique provides double-folded security and the results show that stego image carries a high capacity of secret data with adequate peak signal to noise ratio (PSNR) and lower mean square error (MSE) when compared with existing methods in the literature.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.151-164
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• 2023

Recently, the development of quantum computers means a great threat to existing public key system based on discrete algebra problems or factorization problems. Accordingly, NIST is currently in the process of contesting and screening PQC(Post Quantum Cryptography) that can be implemented in both the computing environment and the upcoming quantum computing environment. Among them, SIKE is the only Isogeny-based cipher and has the advantage of a shorter public key compared to other PQC with the same safety. However, like conventional cryptographic algorithms, all quantum-resistant ciphers must be safe for existing cryptanlysis. In this paper, we studied power analysis-based cryptographic analysis techniques for SIKE, and notably we analyzed SIKE through wavelet transformation and deep learning-based clustering power analysis. As a result, the analysis success rate was close to 100% even in SIKE with applied masking response techniques that defend the accuracy of existing clustering power analysis techniques to around 50%, and it was confirmed that was the strongest attack on SIKE.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.2
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• pp.97-103
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• 2023

Since most of the information is transmitted through the network, eavesdropping and interception by a third party may occur. Appropriate measures are required for effective, secure and confidential communication in the network. Steganography is a technology that prevents third parties from detecting that confidential information is hidden in other media. Due to structural vulnerabilities, information protected by encryption and steganography techniques can be easily exposed to illegitimate groups. In order to improve the limitations of LSB where the simplicity and predictability of the hiding method exist, I propose a technique to improve the security of the message to be hidden based on PRNG and recursive function. To enhance security and confusion, XOR operation was performed on the result of selecting a random bit from the upper bits of the selected channel and the information transformed by the RS-box. PSNR and SSIM were used to confirm the performance of the proposed method. Compared to the reference values, the SSIM and PSNR of the proposed method were 0.9999 and 51.366, respectively, confirming that they were appropriate for hiding information.

• Convergence Security Journal
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• v.23 no.5
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• pp.135-142
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• 2023

In addressing the prominent issues of climate change, resource scarcity, and environmental pollution associated with household waste, extensive research has been conducted on intelligent waste classification methods. These efforts range from traditional classification algorithms to machine learning and neural networks. However, challenges persist in effectively classifying waste in diverse environments and conditions due to insufficient datasets, increased complexity in neural network architectures, and performance limitations for real-world applications. Therefore, this paper proposes i-YOLOX as a solution for rapid classification and improved accuracy. The proposed model is evaluated based on network parameters, detection speed, and accuracy. To achieve this, a dataset comprising 10,000 samples of household waste, spanning 17 waste categories, is created. The i-YOLOX architecture is constructed by introducing the Involution channel convolution operator and the Convolution Branch Attention Module (CBAM) into the YOLOX structure. A comparative analysis is conducted with the performance of the existing YOLO architecture. Experimental results demonstrate that i-YOLOX enhances the detection speed and accuracy of waste objects in complex scenes compared to conventional neural networks. This confirms the effectiveness of the proposed i-YOLOX architecture in the detection and classification of multiple household waste objects.

• The Journal of the Korea Contents Association
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• v.12 no.4
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• pp.60-68
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• 2012

In recent years, the requirements on the high quality environment monitoring by using the sensor nodes which can handle the multimedia data in WSN have been increased. However, because the volume of multimedia data is tremendous, the limited bandwidth of a wireless channel may incur the bottleneck of a system. To solve such a problem, most of the existing distributed multi-path routing protocols based on multimedia data just focused on overcoming the limited bandwidth in order to enhance the energy efficiency and the transmission rate. However, because the existing methods can not apply a key-based technique to encrypt the multimedia data, they are very weak for the security. In this paper, we propose a secure disjointed multipath routing scheme for multimedia data transmission. Since our proposed scheme divides multimedia data(eg. image) into pixels and sends them through disjointed multipath routing, it can provide security to the whole network without using the key-based method. Our experimental results show that our proposed scheme reduces about 10% the amount of the energy consumption and about 65% the amount of the missed data packets caused by malicious nodes over the existing methods on average.