• Journal of Digital Convergence
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• v.10 no.6
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• pp.231-239
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• 2012

This paper tries to solve the problems which previous methods have such as the WCDRM(Watermark and Cryptography DRM) and the model using smart card for protecting digital contents. This study provides a contents distribution model to protect the rights of author, distributor, and user as well as user's information by using technologies such as cryptography, DRM(Digital Right Management), access control, etc. The proposed system is evaluated as the most safety model compared with previous methods because it not only solves the problems which the previous methods have, but also protects four type of risks such as use of contents which other mobile devices download, the attack on the key to decode the message, the attack on leaking the contents, and the internal attack such as an illegal reproduction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1341-1351
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• 2015

As the popularization of smartphone increases the number of various applications, the number of malicious applications also grows rapidly through the third party App Market or black market. This paper suggests an investigation filter, Androfilter, that detects the fabrication of APK file effectively. Whereas the most of antivirus software uses a separate server to collect, analyze, and update malicious applications, Androfilter assumes Google Play as the trusted party and verifies integrity of an application through a simple query to Google Play. Experiment results show that Androfilter blocks brand new malicious applications that have not been reported yet as well as known malicious applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.72-80
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• 2016

Recently, IM(Instant Messenger) of KakaoTalk is being used on smart devices such as smartphones. Because IM service can carry user and/or suspector's various information including life style, geographical position, psychology and crime history, forensic analysis on IM service is desirable. But, forensic analysis for KakaoTalk is not well studied yet. This paper studies a proper forensic method for KakaoTalks, finds artifacts location, reconstruct the list of contacts and the chronology of the messages that have been exchanged by users. Proposed methodology and analyzed information can provide a basic platform for forensic tool.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.258-261
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• 2017

안드로이드 애플리케이션 개발 시 특정 기능을 수행하기 위해 필수적으로 AndroidManifest.xml 파일에 권한을 등록한다. 등록된 권한은 애플리케이션 설치 시 사용자에게 동의를 요구하며 애플리케이션을 설치하기 위해 해당 애플리케이션이 요구하는 사용 권한 모두를 동의해야 한다. 애플리케이션이 요구하는 권한에 동의하지 않을 경우 애플리케이션 설치가 취소되며, 권한 요구에 대한 동의 없이 애플리케이션을 설치할 수 없다. 이러한 이유로 대부분의 사용자는 애플리케이션이 본래의 기능과 맞지 않는 필요 범위 이상으로 요구하는 권한까지도 상세하게 살펴보지 않고 동의하여 본래의 기능과 관계없는 권한을 통해 개인정보 유출, 비정상적인 과금 유발 등 다양한 보안위협이 발생한다. 본 논문에서는 안드로이드 애플리케이션의 APK 파일을 통해 애플리케이션이 요구하는 권한과 실제 애플리케이션이 기능 제공을 위해 사용하는 API 목록을 확인하여 애플리케이션이 필요 범위 이상으로 요구하는 권한을 분석한다. 또한, 애플리케이션 업데이트 시 API 추가로 인해 발생할 수 있는 보안위협을 분석한다. 이를 통해 필요 범위 이상으로 요구하는 권한으로 발생할 수 있는 보안위협에 대해 사전에 인지하여 이를 방지할 수 있도록 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1173-1179
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• 2015

In this paper is given to implements the Android-based integration platform to provide convenience for gender development and scalability , easy access for the user. Sensor-based smart home-related products have a different way of the data exchange so platform can be integrated easily and connect heterogeneous network products and external data transmission security processing for data communication and supported to enable the integration

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.361-371
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• 2017

The increase in user data stored in the device implies the increase in threats of users' sensitive data. Currently, smartphone authentication mechanisms such as Pattern Lock, fingerprint recognition are widely used. Although, there exist disadvantages of inconvenience use and dependence that users need to depend on their own memory. User behavior based authentication mechanism have advantages of high convenience by offering continuous authentication when using the mobile device. However, these mechanisms show limitations on low accuracy of authentication and there are researches to improve the accuracy. This paper proposes improved authentication mechanism that uses user's smartphone application usage pattern which has not considered on earlier studies. Also, we analyze performance of proposed mechanism with collected datasets from actual use of smartphone applications.

• Journal of the Korea Convergence Society
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• v.3 no.2
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• pp.7-12
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• 2012

An advanced and proactive response mechanism against diverse attacks should be proposed for enhance its security and reliability on android based commercial smart work device. In this study, we propose a user-oriented vulnerability analysis and response system on commercial smart work device based on android when diverse attacks are activated. Proposed mechanism uses simplified and optimized memory for monitoring and detecting the abnormal behavior on commercial smart work device, with which we can find and determine the attacker's attempts. Additionally, proposed mechanism provides advanced vulnerability analysis and monitoring/control module.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.257-262
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• 2015

The ministry of security and public administration provide the secure coding guide that can remove the vulnerability of applications and defend cyber attack from the coding step because cyber attack like the hacking about 75% abusing the vulnerability of applications. In this paper we find the oder of priority and did the criticality analysis used by AHP about 7 items in the secure coding which the ministry of security and public administration provide. The result is decided that 'exception handling' is the most important item. There is no secure coding items in software supervision currently, therefore the result of the research will make good use audit standards in the process of the software development.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.4191-4203
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• 2015

WebView is a vital component in smartphone platforms like Android, Windows and iOS that enables smartphone applications (apps) to embed a simple yet powerful web browser inside them. WebView not only provides the same functionalities as web browser, it, more importantly, enables a rich interaction between apps and webpages loaded inside the WebView. However, the design and the features of WebView lays path to tamper the sandbox protection mechanism implemented by browsers. As a consequence, malicious attacks can be launched either against the apps or by the apps through the exploitation of WebView APIs. This paper presents a critical attack called Supplementary Event-Listener Injection (SEI) attack which adds auxiliary event listeners, for executing malicious activities, on the HTML elements in the webpage loaded by the WebView via JavaScript Injection. This paper also proposes an automated static analysis system for analyzing WebView embedded apps to classify the kind of vulnerability possessed by them and a solution for the mitigation of the attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.3
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• pp.643-653
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• 2018

Xamarin is a representative cross-platform development framework that allows developers to write mobile apps in C# for multiple mobile platforms, such as Android, iOS, or Windows Phone. Using Xamarin, mobile app developers can reuse existing C# code and share significant code across multiple platforms, reducing development time and maintenance costs. Meanwhile, malware authors can also use Xamarin to spread malicious apps on more platforms, minimizing the time and cost of malicious app creation. In order to cope with this problem, it is necessary to analyze and detect malware written with Xamarin. However, little studies have been conducted on static analysis methods of the apps written in Xamarin. In this paper, we examine the structure of Android apps written with Xamarin and propose a static analysis technique for the apps. We also demonstrate how to statically reverse-engineer apps that have been transformed using code obfuscation. Because the Android apps written with Xamarin consists of Java bytecode, C# based DLL libraries, and C/C++ based native libraries, we have studied static reverse engineering techniques for these different types of code.