• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1385-1395
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• 2017

This paper aims to develop an IDS (Intrusion Detection System) that takes into account class imbalanced datasets. For this, we first built a set of training data sets from the Kyoto 2006+ dataset in which the amounts of normal data and abnormal (intrusion) data are not balanced. Then, we have run a number of tests to evaluate the effectiveness of machine learning techniques for detecting intrusions. Our evaluation results demonstrated that the Random Forest algorithm achieved the best performances.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.183-191
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• 2012

This study proposes dual certification model using both what users know and what users own. In detail, this mobile OTP generation model is made up of mobile OTP generation and extraction algorithm satisfying the conditions for reviewing mobile OTP implementation. In order to improve the security of the existing OTP-based systems, the suggested method utilizes user's ID and random number at the mobile OTP generation stage.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.959-960
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• 2008

Recently, biometric authentication mechanism has been used to provide high level of security in cryptographic systems. In this paper, we propose an efficient method of generating invariant iris key to be applied in cryptographic systems. In order to generate iris key and improve the performance at the stolen token scenario, multiple random projection technique was combined with multiple linear transformation methods. From the experimental results, we proved that invariant iris keys were generated and the proposed method was robust to stolen token scenario.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1054-1057
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• 2003

A Real Time Mode Selecting Stochastic Controller (RTMSSC) is developed as a new control strategy for a vibrating system under irregular disturbance. Displacement information and frequency characteristics obtained from me::id analysis of the system are used to design a Mode Selecting Controller. This Paper explains design technique of RTNSSC by applying it to the suppression of a flexible beam experiencing random vibration. The RTMSSC is designed by stochastic control from the modal information. The frequency information of the flexible system is utilized from the Mode Selecting Unit (MSU) based on a Fast-Fourier Transformation algorithm. The performance of the proposed technique, RTMSSC, is compared with that of Real Time Stochastic Controller developed recently, which show quite promising results.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.10-14
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• 2012

When tag privacy is required in radio frequency identification (ID) system, a reader needs to identify, and optionally authenticate, a multitude of tags without revealing their IDs. One approach for identification with lightweight tags is that each tag performs pseudo-random function with his unique embedded key. In this case, a reader (or a back-end server) needs to perform a brute-force search for each tag-reader interaction, whose cost gets larger when the number of tags increases. In this paper, we suggest a simple and efficient identification technique that reduces readers computation to $O$(${\sqrt{N}}$ log$N$) without increasing communication cost. Our technique is based on the well-known "meet-in-the-middle" strategy used in the past to attack symmetric ciphers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2750-2759
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• 2009

In this paper, we analyze vulnerabilities in a remote authentication protocol using smartcards which was proposed by Bindu et al. and propose an improved scheme. The proposed scheme can prevent from restricted replay attack and denial of service attack by replacing time stamp with random number. In addition, this protocol can guarantee user anonymity by transmitting encrypted user's ID using AES cipher algorithm. The computational load in our protocol is decreased by removing heavy exponentiation operations and user efficiency is enhanced due to addition of password change phase in which a user can freely change his password. Furthermore, we really implement the proposed authentication protocol using a STM smartcard and authentication server. Then we prove the correctness and effectiveness of the proposed remote authentication system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.241-244
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• 2011

Recently, Due to development of Internet techniques, user suddenly increased that Used of Web services and with out constraints of place and time has been provided. typically, Web services used ID/Password authentication. User confirmed personal data Stored on Web servers after user authorized. web service provider is to provide variety security techniques for the protection personal information. However, recently accident has happened is the malicious attackers may capture user information such as users entered personal information through new keyboard hooking. In this paper, we propose a keyboard hooking protected password input method using CAPTCHA. The proposed password input method is based on entering the password using mouse click or touch pad on the CAPTCHA image. The mapping of CAPTCHA image pixels is random.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.604-611
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• 2017

In wireless sensor networks, an energy efficient operation is important since the energy of the sensors is limited. This paper proposes an energy efficient method that reduces a packet generation with Matrix Completion method where sensor value matrix has low-rank and decreases a collision rate and an overhead by transmitting only sensor ID to a time slot corresponding to the sensor value. Computer simulations demonstrates that the proposed method shows 17% of transmission failure and 73% of the packet generation compared to a conventional CSMA/CS. Delay time of transmitting information of the proposed method exhibits 22% of the CSMA/CA and the MSE error after reconstructing sensor values by Singular Value Thresholding(SVT) in Fusion Center is 87% of the CSMA/CA.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.83-90
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• 2011

Recently, pairings over elliptic curve have been applied for various ID-based encryption/signature/authentication/key agreement schemes. For efficiency, the $Eta_T$ pairings over GF($P^n$) (P = 2, 3) were invented, however, they are vulnerable to side channel attacks such as DPA because of their symmetric computation structure compared to other pairings such as Tate, Ate pairings. Several countermeasures have been proposed to prevent side channel attacks. Especially, Masaaki Shirase's method is very efficient with regard to computational efficiency, however, it has security flaws. This paper examines closely the security flaws of RVA-based countermeasure on $Eta_T$ Pairing algorithm from the implementation point of view.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.73-80
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• 2009

Internet accidents have skyrocketed every year. It always has been threatened by the methods such as hacking and Spyware. The majority of security accident is formed of the loss of authentication information, and the internal user who is not authorized. The importance of security is also emphasized when someone tries to do something accessing to the main information system. Accordingly, Biometrics has been used in many ways. OTP, however, must have a few devices accessing to several systems, and Biometrics involve some risk of mis-recognition rate and mis-denial rate. It also has the risk possible to access to the main information system when losing OTP. This research reduced risks about the loss as separating RFID leader for mobile, Tag and the accessor's cellular phone, and is about pseudo random validation key generated from the administration system through contact with RFID leader for mobile and Tag. As sending the key to user's cell phone which is already registered, security is strengthened more than existing connection methods through the ID and password. RFID for mobile not generalized to the present has been studied as a tool accessing to the main information system.