• The KIPS Transactions:PartD
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• v.9D no.1
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• pp.153-160
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• 2002

This paper describes the design and implementation of library for real-time operating system Q+, that was developed for the internet appliance. The library in the real-time operating system should be defined according to the standard interface and support the functions that are adequate to the real-time application. To ensure the compatibility between application programs, the Q+ library follows industrial and international standards, such as POSIX.1, ISO 7942 GKS. And, to support the Q+ application, library provides C standard functions, graphic/window functions, network functions, security support functions, file system functions. The Q+ library was implemented using the Q+ kernel, Digital TV set-top box, and KBUG debugging tool.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3B
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• pp.199-206
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• 2006

In this paper, we analyzed the weakness of the Back-door type private network which was effective method of system security and transmission speed in the same area without firewall system, and presented the solution to improve it. To prove the effect of this solution, Windows based systems and UNIX based systems are set up in same area, data transmission was tried. According to the result, this solution can maintain the advantage of the Back-door type private network and can have the advantage of removing file server and increasing operation efficiency by reducing the number of operation.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1059-1064
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• 2018

Many users feel a great pain owing to losing edited files. It is very serious loss in time and money. This problem occurs because email attachments are edited in 'Inbox' and the compute immediately shuts down with 'Save'. This is caused by the illusion that the 'save' in a temporary folder is saved to a secure hard disk. Our thesis proposes a loss-prevention system WatchDog for safe storage and folder management of the e-mail attachments. The proposed system operates a warning window pop-up when we 'Open(O)' and 'Save' the attachment. In addition, convenient folder management plans for safe copying and movement are shown through example programs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1279-1284
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• 2009

With the advance of multimedia technology, multimedia sharing among multiple devices has become the main issue. This allows users to expect the peer-to-peer distribution of unprotected and protected contents over public network. Inevitably, this situation has caused an incredible piracy activity and Web sites have begun to provide copyrighted A/V data for free. In order to, protect the contents from illegal attacks and distribution, digital right management (DRM) is required. In this paper, we present the minimal cost scrambling scheme for securing the copyrighted multimedia using the data encryption standard (DES) encryption technique. Experimental results indicate that the proposed scrambling techniques achieve a very good compromise between several desirable properties such as speed, security, and file size.

• Journal of Information Management
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• v.41 no.4
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• pp.205-226
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• 2010

Assuring that the integrity of digital contents is reliably maintained is an important component of long-term digital preservation. The purpose of this study was to examine and analysis the best practices of digital preservation policy and provide the basis theory for establishing a preservation policy for maintaining the integrity of digital contents. In order to achieve the purpose of the study, we examined the digital archiving practices for maintaining the integrity of digital contents. Especially, we focused on the storage media and file formats, the media and format conversion, disaster prevention and recovery, management and handling, inspection and monitoring, and security policies.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.672-675
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• 2013

FTP(File Transfer Protocol)는 호스트에서 다른 호스트로 파일을 전송하기 위한 프로토콜로써, 데이터를 평문으로 전송하기 때문에 기밀성이 보장되지 않는다. 현재 보안 기능이 제공되는 FTP로 FTPS(FTP over SSL)가 있다. FTPS는 TLS(Transport Layer Security)와 SSL(Secure Socket Layer) 암호화 프로토콜 기반에서 동작하는 FTP 이다. 따라서 FTPS는 TLS와 SSL과 같은 추가적인 시스템이 반드시 필요한 단점이 있다. 본 논문에서는 추가적인 암호화 프로토콜 없이 FTP 내에서 보안 기능을 제공하는 Secured FTP를 제안하였다. 본 논문에서 제안한 Secured FTP 는 FTP 내에서 Diffie-Hellman 알고리즘을 이용하여 비밀 키를 교환하고 AES(Advanced Encryption Standard)-Counter 알고리즘을 이용하여 FTP 데이터를 암호화 및 복호화하도록 설계하였다. 본 논문에서 제안한 Secured FTP를 Linux 운영체제에서 구현하였고 시험을 통하여 비밀 키가 정상적으로 교환되고, FTP 데이터가 암호화되어 전송되는 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1286-1306
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• 2022

Searchable symmetric encryption (SSE) provides a safe and effective solution for retrieving encrypted data on cloud servers. However, the existing SSE schemes mainly focus on single keyword search in single client, which is inefficient for multiple keywords and cannot meet the needs for multiple clients. Considering the above drawbacks, we propose a scheme enabling dynamic multi-client and Boolean query in searchable symmetric encryption for cloud storage system (DMC-SSE). DMC-SSE realizes the fine-grained access control of multi-client in SSE by attribute-based encryption (ABE) and novel access control list (ACL), and supports Boolean query of multiple keywords. In addition, DMC-SSE realizes the full dynamic update of client and file. Compared with the existing multi-client schemes, our scheme has the following advantages: 1) Dynamic. DMC-SSE not only supports the dynamic addition or deletion of multiple clients, but also realizes the dynamic update of files. 2) Non-interactivity. After being authorized, the client can query keywords without the help of the data owner and the data owner can dynamically update client's permissions without requiring the client to stay online. At last, the security analysis and experiments results demonstrate that our scheme is safe and efficient.

• Convergence Security Journal
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• v.16 no.4
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• pp.17-24
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• 2016

Many companies and organizations are building a mobile office environment using the LTE network, the national disaster network and Air Force LTE network are built for public safety and national defense. However the recent threats on information security have been evolving from information leakage to DDoS attacks to neutralize the service. Especially, the type of device such as Smart phones, smart pad, tablet PC, and the numbers are growing exponentially and As performance of mobile device and speed of line develop rapidly, DDoS attacks in the mobile environment is becoming a threat. So far, universal countermeasure to DDoS attacks has been interception the network and server step, Yet problem regarding DDoS attack traffic on mobile network and expenditure of network resources still remains. Therefore, this paper analyzes the traffic type distributed in the private mobile network such as the National Disaster Network, and Air Force LTE network in order to preemptively detect DDoS attacks on terminal step. However, as direct analysis on traffic distributed in the National Disaster Network, and Air Force LTE network is restricted, transmission traffics in Minecraft and uploading video file upload which exhibit similar traffic information are analyzed in time series, thereby verifing its effectiveness through establishment of DDoS attacks standard in mobile network and application that detects and protects DDoS attacks

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.21-31
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• 2013

ECU(Electric Control Unit) on the important features of the vehicle is equipped, ECU between sending and receiving messages is connected to one of the internal network(CAN BUS), but this network easily accessible from the outside and not intended to be able to receive attacks from an attacker, In this regard, the development of tools that can be used in order to verify the possibility of attacks on attacks from outside, However, the time costs incurred for developing tools and time to analyze from actual car for CAN messages to be used in the attack to find. In this paper, we want to solve it, propose a method to generate test cases required for the attack is publicly available tool called Sulley and it explains how to find the CAN messages to be used in the attack. Sulley add the CAN messages data generated library files in provided library file and than Sulley execute that make define and execute file conform to the CAN communication preferences and create message rules. Experiments performed by the proposed methodology is applied to the actual car and result, test cases generated by the CAN messages fuzzing through Sulley send in the car and as a result without a separate tool developed was operating the car.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.45-52
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• 2008

In this paper we define a vulnerable code to symbolic link exploit and propose a technique to detect this using program analysis. The existing methods to solve symbolic link exploit is for protecting it, on accessing a temporary file they should perform an investigation whether the file is attacked by symbolic link exploit. If programmers miss the investigation, the program may be revealed to symbolic link exploit. Because our technique detects all the vulnerable codes to symbolic link exploit, it helps programmers keep the program safety. Our technique add two type qualifiers to the existing type system to analyze vulnerable codes to symbolic link exploit, it detects the vulnerable codes using type checking including the added type qualifiers. Our technique detects all the vulnerable codes to symbolic link exploit automatically, it has the advantage of saving costs of modifying and of overviewing all codes because programmers apply the methods protecting symbolic link exploit to only the detected codes as vulnerable. We experiment our analyzer with widely used programs. In our experiments only a portion of all the function fopen() is analyzed as the vulnerabilities to symbolic link exploit. It shows that our technique is useful to diminish modifying codes.