• KIPS Transactions on Software and Data Engineering
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• v.9 no.11
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• pp.351-356
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• 2020

With the spread of COVID-19 infections, the need for next-generation learning management system for undact education is rapidly increasing, and the Ministry of Education is planning future education through the establishment of fourth-generation NEIS. If the fourth-generation NEIS System is well utilized, there are advantages such as providing personalized education services and activating the use of educational data, but a solution to the illegal access problem in an access control environment where strict authorization is difficult due to various user rights. In this paper, we propose a blockchain-based access control audit system for next-generation learning management. Sensitive personal information is encrypted and stored using the proposed system, and when the auditor performs an audit later, a secret key for decryption is issued to ensure auditing. In addition, in order to prevent modification and deletion of stored log information, log information was stored in the blockchain to ensure stability. In this paper, a hierarchical ID-based encryption and a private blockchain are used so that higher-level institutions such as the Ministry of Education can hierarchically manage the access rights of each institution.

• The KIPS Transactions:PartD
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• v.9D no.3
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• pp.477-486
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• 2002

vCard that is the electronic business card automates the exchange of personal information typically found on a traditional business card. vCard information contains not only simple text, but also graphics and multimedia data like pictures, company logos, Web addresses, and so on. This paper describes the design and implementation of Web-based vCard agent system for exchanging vCard, an electronic business card and searching another user's vCard in mobile phone environment. In today's business environment, such as that this information is typically exchanged on business cards. Our web agent system in this paper connect web server which provide vCard service and search, edit vCard information displayed by web browser of mobile phone and exchange vCard with another user through internet. Considering characteristics of wireless devices that have limited storage space, It also saves constructed XML documents that include user's informations in a web server and solves the security problem by exchanging not personal data or XML but encrypted directory name where XML document exits as exchanging vcard.

• Convergence Security Journal
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• v.21 no.1
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• pp.3-7
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• 2021

In quantum cryptographic communication based on quantum mechanics, each piece of information is loaded onto individual photons and transmitted. Therefore, it is impossible to eavesdrop on only a part, and even if an intruder illegally intercepts a photon and retransmits it to the recipient, it is impossible to send the same information to the photon by the principle of quantum duplication impossible. With the explosive increase of various network-based services, the security of the service is required to be guaranteed, and the establishment of a quantum cryptographic communication network and related services are being promoted in various forms. However, apart from the development of Quantum Key Distribution (QKD) technology, a lot of research is needed on how to provide network-level services using this. In this paper, based on the quantum encryption device, we propose an integrated data structure for transferring quantum keys between various quantum encryption communication network devices and realizing an encrypted transmission environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.729-738
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• 2019

In this paper, we propose two-way authentication protocol between unmanned systems in tactical wireless networks in which long distance communications are not guaranteed due to a poor channel conditions. It is assumed that every unmanned systems have same random data set before they put into combat. The proposed protocol generates authentication code(AC) using random data that causes hash collision. The requester for authentication encrypts the materials such as their identifier, time-stamp, authentication code with the secret key. After then the requester transmits the encrypted message to the receiver. The receiver authenticates the requester by verifying the authentication code included in the request message. The performance analysis of the proposed protocol shows that it guarantees the security for various attack scenarios and efficiency in terms of communication overhead and computational cost. Furthermore, we analyzed the effect of the parameter values of the proposed protocol on the performance and suggest appropriate parameter value selection guide according to the level of security requirement.

• Convergence Security Journal
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• v.17 no.5
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• pp.101-110
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• 2017

The purpose of this study is to examine possibilities of industry secret information leakage through IoT devices and to prevent information leakage from the perspective of administrative and technique security. From the administrative security perspective, first, it is important to face the possibility of industry information data leakage through anyone who can access companies and should establish guidelines to limit the use of IoT devices when entering companies. Second, security management guideline should be prepared by companies or upon user's request and use of any electronic devices sharing wireless internet connection should be eliminated or restricted. From technique security perspective, channels that sharing IoT devices in computers should be controlled since industry secret information are stored in computers and servers. Furthermore, IoT devices that accessing wireless internet network or devices that already registered should be regularly checked in order to minimize any information leakage. Lastly, data and information stored in computers and servers should be encrypted.

• Convergence Security Journal
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• v.21 no.1
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• pp.33-44
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• 2021

Data outsourcing utilizing the Cloud faces a problem of the third-party exposure, modulation, and reliability for the provided computational delegation results. In order to solve those problematic security issues, homomorphic encryption(HE) which executes calculation and analysis on encrypted data becomes popular. By extension, a new type of HE with a authentication functionality, homomorphic authenticated encryption(HAE) is suggested. However, a research on the HAE is on the initial stage. Furthermore, based on a message authenticated scheme with HE, the method and analysis to design is still absent. This paper aims to analyze an HAE, with a generic combination of a message authenticated scheme and a HE, known as "Encrypt with Authentication". Following a series of analysis, we show that by adopting a unforgeable message authenticated scheme, the generically constructed HAE demonstrated an unforgeability as well. Though, a strong unforgeability is not the case. This paper concludes that although indistinguishable HE can be applied to design the HAE, a security issue on the possibility of indistinguishability is still not satisfied.

• Convergence Security Journal
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• v.21 no.2
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• pp.29-35
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• 2021

UART (Universal asynchronous receiver/transmitter) is a hardware device that converts data into serial format and transmits it, and is widely used for system diagnosis and debugging in most embedded systems. Hackers can access system memory or firmware by using the functions of UART, and can take over the system by acquiring administrator rights of the system. In this paper, we studied secure UART to protect against hacker attacks through UART. In the proposed scheme, only authorized users using the promised UART communication protocol are allowed to access UART and unauthorized access is not allowed. In addition, data is encrypted and transmitted to prevent protocol analysis through sniffing. The proposed UART technique was implemented in an embedded Linux system and performance evaluation was performed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.4
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• pp.127-138
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• 2006

The IPSec is a basic security mechanism of the IPv6 protocol, which can guarantee an integrity and confidentiality of data that transmit between two corresponding hosts. Also, both data and communication subjects can be authenticated using the IPSec mechanism. However, it is difficult that the IPSec mechanism protects major important network from attacks which transmit mass abnormal IPSec traffic in session-configuration or communication phases. In this paper, we present a design of the security system that can effectively detect and defeat abnormal IPSec traffic, which is encrypted by the ESP extension header, using the IPSec Session and Configuration table without any decryption. This security system is closely based on a multi-tier attack mitigation mechanism which is based on network bandwidth management and aims to counteract DDoS attacks and DoS effects of worm activity.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.184-186
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• 2022

Recently, as interest in personal information protection has increased, various apps for personal information protection have emerged. These apps protect data in various formats, such as photos, videos, and documents containing personal information, using encryption and hide functions. These apps can have a positive effect on personal information protection, but in digital forensics, they act as anti-forensic because they can be difficult to analyze data during the investigation process. In this paper, finds out PIN, an access control function, through reverse engineering on Calculator - photo vault, one of the personal information protection apps, and files such as photos and documents to which encryption and hide were applied. In addition, the vulnerability to this app was analyzed by research decryption for database files where logs for encrypted and hide files are stored.