• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.5
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• pp.81-88
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• 2010

Sun et al. proposed a new design of wearable token system for security of mobile devices, such as a notebook and PDA. In this paper, we show that Sun et al.'s system is vulnerable to off-line password guessing attack and man in the middle attack based on known plain-text attack. We propose an improved scheme which overcomes the weaknesses of Sun et al.'s system. The proposed protocol requires to perform one modular multiplication in the wearable token, which has low computation ability, and modular exponentiation in the mobile devices, which have sufficient computing resources. Our protocol has no security problem, which threatens Sun's system, and known vulnerabilities. That is, the proposed protocol overcomes the security problems of Sun's system with minimal overheads.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.145-154
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• 2010

End-to-End(E2E) encryption is to encrypt private and important financial information such as user's secret access numbers and account numbers from user's terminal to financial institutions. There has been found significant security vulnerabilities by various hacking in early E2E encryption system since early E2E encryption is not satisfied the basic security requirement which is that there does not exist user's financial information on plaintext in user's terminal. Extensional E2E encryption which is to improve early E2E encryption provides confidentiality and integrity to protect user's financial information from vulnerabilities such as alteration, forgery and leakage of confidential information. In this paper, we explain the extensional E2E encryption technology and present considerable security issues when the extensional E2E encryption technology is applied to financial systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.391-404
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• 2022

Aron Gohr proposed a cryptanalysis method based on deep learning technology for the lightweight block cipher Speck. This is a method that enables a chosen plaintext attack with higher accuracy than the classical differential cryptanalysis. In this paper, by using the probability distribution, we analyze the mechanism of such deep learning based cryptanalysis and propose the results applied to the lightweight block cipher Simon. In addition, we examine that the probability distributions of the predicted values of the neural networks within the cryptanalysis working processes are different depending upon the characteristics of round functions of Speck and Simon, and suggest a direction to improve the efficiency of the neural distinguisher which is the core technology of Aron Gohr's cryptanalysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1382-1391
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• 2022

White-box cryptography can respond to white-box attacks that can access and modify memory by safely hiding keys in the lookup table. However, because the size of lookup tables is large and the speed of encryption is slow, it is difficult to apply them to devices that require real-time while having limited resources, such as IoT(Internet of Things) devices. In this work, we propose a scheme for collecting short-length plaintexts and processing them at once, utilizing the characteristics that white-box ciphers process encryption on a lookup table size basis. As a result of comparing the proposed method, assuming that the table sizes of the Chow and XiaoLai schemes were 720KB(Kilobytes) and 18,000KB, respectively, memory usage reduced by about 29.9% and 1.24% on average in the Chow and XiaoLai schemes. The latency was decreased by about 3.36% and about 2.6% on average in the Chow and XiaoLai schemes, respectively, at a Traffic Load Rate of 15 Mbps(Mega bit per second) or higher.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.6
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• pp.1113-1120
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• 2022

Recently, the investigation has been difficult due to the emergence of messengers that encrypt and store data for the purpose of protecting personal information and provide services such as end-to-end encryption with a focus on security. Accordingly, the number of crime cases using security messengers is increasing, but research on data decoding for security messengers is needed. Element security messengers provide end-to-end encryption functions so that only conversation participants can check conversation history, but research on decoding them is insufficient. Therefore, in this paper, we analyze the instant messenger Element, which provides end-to-end encryption, and propose a plaintext verification of the history of encrypted secure chat rooms using decryption keys stored in the Windows Credential Manager service without user passwords. In addition, we summarize the results of analyzing significant general and secure chat-related artifacts from a digital forensics investigation perspective.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.807-816
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• 2022

See-In-The-Middle (SITM) is an analysis technique that uses Side-Channel information for differential cryptanalysis. This attack collects unmasked middle-round power traces when implementing block ciphers to select plaintext pairs that satisfy the attacker's differential pattern and utilize them for differential cryptanalysis to recover the key. Romulus, one of the final candidates for the NIST Lightweight Cryptography standardization competition, is based on Tweakable block cipher Skinny-128-384+. In this paper, the SITM attack is applied to Skinny-128-384 implemented with 14-round partial masking. This attack not only increased depth by one round, but also significantly reduced the time/data complexity to 2^14.93/2^14.93. Depth refers to the round position of the block cipher that collects the power trace, and it is possible to measure the appropriate number of masking rounds required when applying the masking technique to counter this attack. Furthermore, we extend the attack to Romulus's Nonce-based AE mode Romulus-N, and Tweakey's structural features show that it can attack with less complexity than Skinny-128-384.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.845-853
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• 2022

As the memory capacity of smartphone increases, the type and amount of privacy stored in the smartphone is also increasing. but recently there is an increasing possibility that various personal information such as photos and videos of smartphones may be leaked due to malicious apps by malicious attackers or other people such as repair technicians. This paper analyzed and studied the security and vulnerability of these vault apps by analyzing the cryptography algorithm and data protection function. We analyzed 5.3.7(June 13, 2022) and 3.3.2(December 30, 2020) versions of AppLock, the most downloaded information-hidding apps registered with Google Play, and found various vulnerabilities. In the case of access control, there was a vulnerability in that values for encrypting patterns entered by users were hardcoded into plain text in the source code, and encrypted pattern values were stored in xml files. In addition, in the case of the vault function, there was a vulnerability in that the files and log files for storing in the vault were not encrypted.

• Journal of the Korea Society of Computer and Information
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• v.28 no.11
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• pp.65-71
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• 2023

In this paper, we design and implement the Walking Life Festival application, which is based on the Android platform and provides information about domestic travel destinations and regional festivals in South Korea. This application utilizes various sensors found in smartphones, including the Step Counter sensor, Step Detector sensor, Acceleration sensor, and GPS sensor. Additionally, it makes use of Google Map API and Public Open API to offer information about domestic travel destinations and local festivals. The application also incorporates an automatic login feature using the Shared Preference API. When storing login information in the database, it encrypts the input plaintext data using a hash algorithm. For Google Maps integration, it creates objects using the Google.maps.LatLngBounds() method and extends the location information through the extends method. Furthermore, this application contributes to the activation of the domestic tourism industry by notifying users about the timing of local festivals related to domestic travel destinations, thus increasing their opportunities to participate in these festivals.

• Trans-
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• v.16
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• pp.135-162
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• 2024

This study examines the concepts and characteristics of Interculturalism and extracts artistic expressions of intercultural characteristics shown in Nouvelle Danse and Non-Danse, which were the birthplace of the contemporary dance flow in Europe. The discussion and composition of these dances will be analyzed from an intercultural perspective by selecting three works by each choreographer representing Nouvelle Danse and Non- Danse. In doing so, we would like to examine what creative acceptance was achieved based on the values and understanding in the clash and encounter between different cultures in art. Dance and interculturalism emphasize exchanges and encounters between one's own culture and other cultures. In addition, it has the potential to contribute to dance studies through the humanistic perspective of dance, as it also contains issues about diversity and identity due to exchange between cultures at the center of globalization. Therefore, the purpose of the study is to read the artistic expressions of choreographers in Nouvelle d'Anse and Non-d'Anse through intercultural understanding with an in-depth understanding and to interpret them by adding multi-layered time to the study.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.4
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• pp.569-575
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• 2024

The 64-bit block cipher IIoTBC is an encryption algorithm designed for the security of industrial IoT devices and uses an 128-bit secret key. The IIoTBC's encryption algorithm varies depending on whether the MCU size used in IoT is 8-bit or 16-bit. This paper deals with a differential attack on IIoTBC when the MCU size is 8-bit. It attacks 15-round out of the entire 32-round using IIoTBC's 14-round differential characteristic. At this time, the number of required plaintexts and encryption are 2⁵⁷ and 2^122.4, respectively. The differential characteristic presented in this paper has a longer round than the existing 13-round impossible differential characteristic, and the attack using this is the result of the first key recovery attack on IIoTBC.