• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.339-344
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• 2019

In order to prepare for the rise of data security threats caused by the information and communication technology, technology that can guarantee the stability of the data stored in the missile test set is important. For this purpose, encryption should be performed when data is stored so that it cannot be restored even if data is leaked, and integrity should be ensured even after decrypting the data. In this paper, we apply AES algorithm, which is a symmetric key cryptography system, to the missile test set, and Encrypt and decrypt according to the amount of data for each bit of each AES algorithm. We implemented the AES Rijndael algorithm in the existing inspection system to analyze the effect of encryption and apply the proposed encryption algorithm to the existing system. confirmation of suitability. analysis of capacity and Algorithm bits it is confirmed that the proposed algorithm will not affect the system operation and the optimal algorithm is derived. compared with the initial data, we can confirm that the algorithm can guarantee data undulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.370-378
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• 2008

The CEDA(Certified E-Document Authority) is a reliable third party that deposit electronic document having legal effects securely, and verify contents of document or transmission. This paper focuses on a function of secure transmission among several important functions, and implements public key encryption system for secure transmission when server and user communicate for image transmission. This paper follows a standard fundamental rule of X.509 in ITU-T, and it uses symmetric encryption algorithm to raise speed of a large data operation. A key of symmetric encryption algorithm is encrypted by private key in public key system, it protects to be modified using digital signature for data integrity. Also it uses certificates for mutual authentication.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1238-1246
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• 2005

This thesis is written with web security module for safe data transmission between heterogeneous systems(ex. OS). Web system has allowed users to have great convenience and a lot of information. Though web service business has been progressed much, because of the limitation of it's own system, lots of loss, derived from data spillage which is the weakest point of security, has also followed. Suggested security module is realized by two module. One for server security module for web server, the other is client security module for client. The security structure, suggested on this thesis guarantee safe data transmission by only simple installation of modules in clients and servers. for speed sensitive transmission between web server and browser, Triple-DES, symmetric encryption system suitable for fast encryption communication, is adapted. To solve problems caused from key management, Diffie-Hellman's key exchange algorithm is adapted. By this method, all symmetric encryption troubles from key distribution and management, speed could be work out a solution. And Diffie-Hellman type algorithm secures Authentication for safe data Protection.

• Journal of Internet of Things and Convergence
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• v.2 no.3
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• pp.43-51
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• 2016

In this paper, we have developed Crypft+ as an enhanced file encryption/decryption system to improve the security of IoT system or individual document file management process. The Crypft+ system was developed as a core security module using Python, and designed and implemented a user interface using PyQt. We also implemented encryption and decryption function of important files stored in the computer system using AES based symmetric key encryption algorithm and SHA-512 based hash algorithm. In addition, Cx-Freezes module is used to convert the program as an exe-based executable code. Additionally, the manual for understanding the Cryptft+ SW is included in the internal program so that it can be downloaded directly.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.843-850
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• 2006

This is devoted to first, to propose a hash chain algorithm that generates more secure key than conventional encryption method. Secondly, we proposes encryption method that is more secure than conventional system using a encryption method that encrypts each block with each key generated by a hash chain algorithm. Thirdly, After identifying the user via wired and wireless network using a user authentication method. We propose a divided session key method so that Although a client key is disclosed, Attackers cannot catch a complete key and method to safely transfer the key using a divided key method. We make an experiment using various size of digital contents files for performance analysis after performing the design and implementation of system. Proposed system can distribute key securely than conventional system and encrypt data to prevent attacker from decrypting complete data although key may be disclosed. The encryption and decryption time that client system takes to replay video data fie is analogous to the conventional method.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.91-96
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• 1998

In this paper we designed a secure client-server system to be able to protect messages between client and server using cryptography We authenticated each other using a asymmetric encryption algorithm on the logon procedure and minimized the time to encrypt and decrypt messages using a symmetric encryption algorithm on exchanging messages. We proved that it is possible to make a digital signature on our secure client-server system. And we suggested the efficient key management method to generate and distribute cryptograpic key securely.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.55-60
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• 2020

In this paper, we propose an access control system using cryptography as a method to protect personal data in public blockchain. The proposed system is designed to encrypt data according to the access policy, store it in the blockchain, and decrypt only the person who satisfy the access policy. In order to improve performance and scalability, an encryption mechanism is implemented outside the blockchain. Therefore, data access performance could be preserved while cryptographic operations executed Furthermore it can also improve the scalability by adding new access control modules while preserving the current configuration of blockchain network. The encryption scheme is based on the attribute-based encryption (ABE). However, unlike the traditional ABE, the "retention period", is incorporated into the access structure to ensure the right to be forgotten. In addition, symmetric key cryptograpic algorithms are used for the performance of ABE. We implemented the proposed system in a public blockchain and conducted the performance evaluation.

• ETRI Journal
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• v.37 no.4
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• pp.696-706
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• 2015

This paper presents an achievable secure videoconferencing system based on quantum key encryption in which key management can be directly applied and embedded in a server/client videoconferencing model using, for example, OpenMeeting. A secure key management methodology is proposed to ensure both a trusted quantum network and a secure videoconferencing system. The proposed methodology presents architecture on how to share secret keys between key management servers and distant parties in a secure domain without transmitting any secrets over insecure channels. The advantages of the proposed secure key management methodology overcome the limitations of quantum point-to-point key sharing by simultaneously distributing keys to multiple users; thus, it makes quantum cryptography a more practical and secure solution. The time required for the encryption and decryption may cause a few seconds delay in video transmission, but this proposed method protects against adversary attacks.

• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.167-172
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• 2008

Fingerprinting scheme supports the copyright protection to track redistributors of digital content using cryptographic techniques. Fingerprinting schemes should guarantee buyer's anonymity and asymmetry for their privacy. Most of known fingerprinting schemes adopt public-key cryptosystems to achieve asymmetry and discrete logarithm problem or graph isomorphism problem to achieve anonymity. However, these schemes are not suited in mobile environment because of the drawbacks of requiring high computational complexity. In this paper, we propose an efficient fingerprinting scheme for mobile environment to provide not only asymmetry of the protocol but also transaction anonymity of the buyer. By employing symmetric encryption to encrypt the digital content and adopting agent to perform the protocols, the efficiency of the proposed scheme is improved.

• Journal of Information Processing Systems
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• v.12 no.4
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• pp.688-710
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• 2016

Our approach permits to capitalize the expert's knowledge as business rules by using an agent-based platform. The objective of our approach is to allow experts to manage the daily evolutions of business domains without having to use a technician, and to allow them to be implied, and to participate in the development of the application to accomplish the daily tasks of their work. Therefore, the manipulation of an expert's knowledge generates the need for information security and other associated technologies. The notion of cryptography has emerged as a basic concept in business rules modeling. The purpose of this paper is to present a cryptographic algorithm based approach to integrate the security aspect in business rules modeling. We propose integrating an agent-based approach in the framework. This solution utilizes a security agent with domain ontology. This agent applies an encryption/decryption algorithm to allow for the confidentiality, authenticity, and integrity of the most important rules. To increase the security of these rules, we used hybrid cryptography in order to take advantage of symmetric and asymmetric algorithms. We performed some experiments to find the best encryption algorithm, which provides improvement in terms of response time, space memory, and security.