• Journal of the Korea Society of Computer and Information
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• v.17 no.11
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• pp.101-105
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• 2012

Various social problems through violating personal information and privacy are growing with the rapid spread of smartphones. For this reason, variety of researches and technology developments to protect personal information being made. The smartphone, contains almost all of the personal information, can cause data spill at any time. Collecting or analyzing evidence is not an easy job with forensic analyzing tool. Android forensics research has been focused on techniques to collect and analyze data from non-volatile memory but research for volatile data is very slight. Android log is the non-volatile data that can be collected by volatile storage. It is enough to use as a material to track the usage of the Android phone because all of the recent driven records from system to application are stored. In this paper, we propose a method to respond to determining the existence of personal information leakage by filtering logs without forensic analysis tools.

• Journal of KIISE
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• v.42 no.9
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• pp.1100-1108
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• 2015

Classes.dex, which is the executable file for android operation system, has Java bite code format, so that anyone can analyze and modify its source codes by using reverse engineering. Due to this characteristic, many android applications using classes.dex as executable file have been illegally copied and distributed, causing damage to the developers and software industry. To tackle such ill-intended behavior, this paper proposes a technique to encrypt classes.dex file using an AES(Advanced Encryption Standard) encryption algorithm and decrypts the applications encrypted in such a manner in order to prevent reverse engineering of the applications. To reinforce the file against reverse engineering attack, hash values that are obtained from substituting a hash equation through the combination of salt values, are used for the keys for encrypting and decrypting classes.dex. The experiments demonstrated that the proposed technique is effective in preventing the illegal duplication of classes.dex-based android applications and reverse engineering attack. As a result, the proposed technique can protect the source of an application and also prevent the spreading of malicious codes due to repackaging attack.

• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.61-68
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• 2019

Although the number of smartphone users is continuously increasing due to the advantage of being able to easily use most of the Internet services, the number of counterfeit applications is rapidly increasing and personal information stored in the smartphone is leaked to the outside. Because Android app was developed with Java language, it is relatively easy to create counterfeit apps if attacker performs the de-compilation process to reverse app by abusing the repackaging vulnerability. Although an obfuscation technique can be applied to prevent this, but most mobile apps are not adopted. Therefore, it is fundamentally impossible to block repackaging attacks on Android mobile apps. In addition, personal information stored in the smartphone is leaked outside because it does not provide a forgery self-verification procedure on installing an app in smartphone. In order to solve this problem, blockchain is used to implement a process of certificated application registration and a fake app identification and detection mechanism is proposed on Hyperledger Fabric framework.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.907-913
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• 2022

Approximately 70% of smartphone users around the world use Android operating system-based smartphones, and malicious apps targeting these Android platforms are constantly increasing. Google has provided "Google Play Protect" to respond to the increasing number of Android targeted malware, preventing malicious apps from being installed on smartphones, but many malicious apps are still normal. It threatens the smartphones of ordinary users registered in the Google Play store by disguising themselves as apps. However, most people rely on antivirus programs to detect malicious apps because the average user needs a great deal of expertise to check for malicious apps. Therefore, in this paper, we propose a method to classify unnecessary malicious permissions of apps by using only the categories and permissions that can be easily confirmed by the app, and to easily detect malicious apps through the classified permissions. The proposed method is compared and analyzed from the viewpoint of undiscovered rate and false positives with the "commercial malicious application detection program", and the performance level is presented.

• Journal of the Korea Society of Computer and Information
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• v.28 no.7
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• pp.85-93
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• 2023

Software birthmark refers to a unique feature inherent in software that can be extracted from program binaries even in the absence of the original source code of the program. Like human genetic information, the similarity between programs can be calculated numerically, so it can be used to determine whether software is stolen or copied. In this paper, we propose a new birthmark technique for Android applications developed using Unity. The source codes of Unity-based Android applications use C# language, and since the core logic of the program is included in the DLL module, it must be approached in a different way from normal Android applications. In this paper, a Unity birthmark extraction and comparison system was implemented, and reliability and resilience were evaluated. The use of the Unity birthmark technique proposed in this paper is expected to be effective in preventing illegal copy or code theft of the Unity-based Android applications.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.609-616
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• 2012

Plumbing of the plant project is an important discipline. Now workers on the construction site, carry hundreds of piping spool drawings and documents, record the Spool Stage data. Then, The data is input into the system or has been documented in the field office. Because of the work-flow, duplication work occurs. As a result, it is reducing the effectiveness of the Plumbing and causes schedule delays. Also, To manage the integration process, there is a problem, it takes a lot of time. Therefore, The study is conducted to design and implementation of piping spool management Android Application using QR Code. The Application will contribute to the management to the integration of piping work process.

• 한국정보교육학회:학술대회논문집
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• 2011.01a
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• pp.153-158
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• 2011

The idea that the mobile phone could be used in the education field recently comes from it's strengths. They have mobility, on-the-spot-study, portablity, immediacy and they are easy to connect to educational information. The application which I developed in this study is using Google-Map API and is based on GPS. It can share the information about the area where user is located like text data and pictures of geography, culture, and historical remains. This application makes the best use of the mobile phone's strengths. It's more effective and we can expect that users could manage resources of learning and do self-directed study in spite of being outside of the classroom or after regular classtime.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.13-19
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• 2014

Improvement of performances of potable communication devices such as laptops, tablets, and smart-phones enables people to do group meetings in any place. However, even though group members in a meeting locate close, data or information to be shared in the group are exchanged through the cellular networks. This increases unnecessary traffic loads in the wireless/backbone networks and as consequence it increase delays in communications. To resolve the problem, an android-based application is developed in this paper. The application utilizes Wi-Fi Direct so that all members in the meeting can direct exchange materials for the meeting without using cellular networks.

• Journal of Advanced Navigation Technology
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• v.16 no.1
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• pp.163-170
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• 2012

This thesis suggests the application to the people who are using smart phone which is based on the Android operation system that makes it available to check their call and sms by a repeater and display in the limited places such as at the swimming pool or spa. This application is designed to save user's basic information. And when the user gets a call or a sms, it can make the sender number and fundamental information a data by PhonStateListener and SmsReceiver. The data is uploaded by bluetooth of a repeater. The smart phone user can use the repeater to check the received information by display.

• 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.