• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.157-164
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• 2023

In modern society, smart home has become a part of people's daily life. But traditional smart home systems often have problems such as security, data centralization and easy tampering, so a blockchain is an emerging technology that solves the problems. This paper proposes a blockchain-based smart home system which consists in a home and a blockchain network part. The blockchain network with 8 nodes is implemented by HyperLeger Fabric platform on Docker. ECC(Elliptic Curve Cryptography) technology is used for data transmission security and RBAC(role-based access control) manages the certificates of network members. Raft consensus algorithm maintains data consistency across all nodes in a distributed system and reduces block generation time. The query and data submission are controlled by the smart contract which allows nodes to safely and efficiently access smart home data. The experimental results show that the proposed system maintains a stable average query and submit time of 84.5 [ms] and 93.67 [ms] under high concurrent accesses, respectively and the transmission data is secured through simulated packet capture attacks.

• Journal of Internet of Things and Convergence
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• v.9 no.1
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• pp.1-7
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• 2023

Cases in which personal terminals or servers are infected by ransomware are rapidly increasing. Ransomware uses a self-developed encryption module or combines existing symmetric key/public key encryption modules to illegally encrypt files stored in the victim system using a key known only to the attacker. Therefore, in order to decrypt it, it is necessary to know the value of the key used, and since the process of finding the decryption key takes a lot of time, financial costs are eventually paid. At this time, most of the ransomware malware is included in a hidden form in binary files, so when the program is executed, the user is infected with the malicious code without even knowing it. Therefore, in order to respond to ransomware attacks in the form of binary files, it is necessary to identify the encryption module used. Therefore, in this study, we developed a mechanism that can detect and identify by reverse analyzing the encryption module applied to the malicious code hidden in the binary file.

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.871-874
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• 2011

The fast emerging of network technology and the high demand of computing resources have prompted many organizations to outsource their storage and computing needs. Cloud based storage services such as Microsoft's Azure and Amazon's S3 allow customers to store and retrieve any amount of data, at anytime from anywhere via internet. The scalable and dynamic of the cloud storage services help their customer to reduce IT administration and maintenance costs. No doubt, cloud based storage services brought a lot of benefits to its customer by significantly reducing cost through optimization increased operating and economic efficiencies. However without appropriate security and privacy solution in place, it could become major issues to the organization. As data get produced, transferred and stored at off premise and multi tenant cloud based storage, it becomes vulnerable to unauthorized disclosure and unauthorized modification. An attacker able to change or modify data while data inflight or when data is stored on disk, so it is very important to secure data during its entire life-cycle. The traditional cryptography primitives for the purpose of data security protection cannot be directly adopted due to user's lose control of data under off premises cloud server. Secondly cloud based storage is not just a third party data warehouse, the data stored in cloud are frequently update by the users and lastly cloud computing is running in a simultaneous, cooperated and distributed manner. In our proposed mechanism we protect the integrity, authentication and confidentiality of cloud based data with the encrypt- then-upload concept. We modified and applied proxy re-encryption protocol in our proposed scheme. The whole process does not reveal the clear data to any third party including the cloud provider at any stage, this helps to make sure only the authorized user who own corresponding token able to access the data as well as preventing data from being shared without any permission from data owner. Besides, preventing the cloud storage providers from unauthorized access and making illegal authorization to access the data, our scheme also protect the data integrity by using hash function.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1611-1633
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• 2022

At EUROCRYPT 2019, a new block cipher algorithm called BISON was proposed by Canteaut et al. which uses a novel structure named as Whitened Swap-Or-Not (WSN). Unlike the traditional wide trail strategy, the differential and linear properties of this algorithm can be easily determined. However, the encryption speed of the BISON algorithm is quite low due to a large number of iterative rounds needed to ensure certain security margins. Commonly, denoting by n is the data block length, this design requires 3n encryption rounds. Moreover, the block size n of BISON is always odd, which is not convenient for operations performed on a byte level. In order to overcome these issues, we propose a new block cipher, named DBISON, which more efficiently employs the ideas of double layers typical to the BISON-like construction. More precisely, DBISON divides the input into two parts of size n/2 bits and performs the round computations in parallel, which leads to an increased encryption speed. In particular, the data block length n of DBISON can be even, which gives certain additional implementation benefits over BISON. Furthermore, the resistance of DBISON against differential and linear attacks is also investigated. It is shown the maximal differential probability (MDP) is 1/2^n-1 for n encryption rounds and that the maximal linear probability (MLP) is strictly less than 1/2^n-1 when (n/2+3) iterative encryption rounds are used. These estimates are very close to the ideal values when n is close to 256.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.219-228
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• 2022

One of the most pressing and demanding issues today in the conditions of widespread transformation and digitalization of spheres of human activity is information security and ensuring the integrity of data. The main research and development in the field of information security is aimed at improving efficiency and rationalization. One of the main means of data transmission and operation of information complexes are fiber-optic systems. To date, there have been incidents of illegal intrusion and theft of information, passing through this type of communication. Thus, today there is a problem associated with insufficient information security in fiber-optic data transmission systems. One of the most effective tools to counter acts of illegal interference in systems are artificial intelligence and cryptographic algorithms of information protection. It is the symbiosis of these two tools that can qualitatively improve the level of information security in fiber-optic data transmission systems. Thus, the authors of this article pursue the goal associated with the description of an innovative system for protecting information from violations in fiber-optic data transmission systems based on the integration of intelligent cryptographic algorithms.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.3
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• pp.461-470
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• 2016

As IoT is broadly used in many fields, the security of IoT is becoming especially important and critical issues. Security and privacy are the key issues for IoT applications, and still faced with some enormous challenges. Sensor has limited resources such as computing power, memory, battery. By means of deeply analyzing the security architecture and features in security framework. While a number of researchers have explored such security challenges and open problems in IoT, there is an unfortunate lack of a systematic study of the security challenges in the IoT landscape. This special issue features recent and emerging advances IoT architecture, protocols, services and applications. The alternative method is IoT security gateway. In this paper, we surveyed the demands and requirements. By means of deeply analyzing the security architecture and features, we analyzed the demands and requirements for security based on gateway application.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.1
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• pp.13-31
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• 2023

Korean Government-PKI (GPKI) is a public-key infrastructure which provides authentication and security functions for information system used by central government, local governments, and public institutions of the Republic of Korea to provide their own administrative and public services. The current cryptosystem of GPKI was established in the early 2000s, and more than ten years have passed since the last improvement in 2010. Over the past decade or so, the information security, including cryptography, has undergone many changes and will continue to face many changes. Therefore, for the sustainable security of GPKI, it is necessary to review the security of the cryptosystem at this point. In this paper, we analyze the current status and the security of technologies and standards used in the system. We identify cryptographic algorithms with degraded security, international standards which are obsoleted or updated, and cryptographic parameters that should be revised for the high security level. And based on this, we make several suggestions on the reorganization of cryptographic algorithms and related technologies for the security enhancement of GPKI.

• International Journal of Computer Science & Network Security
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• v.23 no.7
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• pp.49-60
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• 2023

The amount of data generated by electronic systems through e-commerce, social networks, and data computation has risen. However, the security of data has always been a challenge. The problem is not with the quantity of data but how to secure the data by ensuring its confidentiality and privacy. Though there are several research on cloud data security, this study proposes a security scheme with the lowest execution time. The approach employs a non-linear time complexity to achieve data confidentiality and privacy. A symmetric algorithm dubbed the Non-Deterministic Cryptographic Scheme (NCS) is proposed to address the increased execution time of existing cryptographic schemes. NCS has linear time complexity with a low and unpredicted trend of execution times. It achieves confidentiality and privacy of data on the cloud by converting the plaintext into Ciphertext with a small number of iterations thereby decreasing the execution time but with high security. The algorithm is based on Good Prime Numbers, Linear Congruential Generator (LGC), Sliding Window Algorithm (SWA), and XOR gate. For the implementation in C, thirty different execution times were performed and their average was taken. A comparative analysis of the NCS was performed against AES, DES, and RSA algorithms based on key sizes of 128kb, 256kb, and 512kb using the dataset from Kaggle. The results showed the proposed NCS execution times were lower in comparison to AES, which had better execution time than DES with RSA having the longest. Contrary, to existing knowledge that execution time is relative to data size, the results obtained from the experiment indicated otherwise for the proposed NCS algorithm. With data sizes of 128kb, 256kb, and 512kb, the execution times in milliseconds were 38, 711, and 378 respectively. This validates the NCS as a Non-Deterministic Cryptographic Algorithm. The study findings hence are in support of the argument that data size does not determine the execution.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.6
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• pp.869-879
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• 2023

Sparkle is one of the finalists in the Lightweight Cryptography Standardization Process conducted by NIST. It is a nonlinear permutation and serves as a core component for the authenticated encryption algorithm Schwaemm and the hash function Esch. In this paper, we provide specific forms of input and output differences for 6 rounds of Sparkle384 and 7 rounds of Sparkle512, and make formulas for the complexity of finding input pairs that satisfy these differentials. Due to the significantly lower complexity compared to similar tasks for random permutations with the same input and output sizes, they can be valid distinguishing attacks. The numbers(6 and 7) of attacked rounds are very close to the minimum numbers(7 and 8) of really used rounds.