• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.168-182
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• 2020

Spoofing attacks, especially replay attacks, pose great security challenges to automatic speaker verification (ASV) systems. Current works on replay attacks detection primarily focused on either developing new features or improving classifier performance, ignoring the effects of feature variability, e.g., the channel variability. In this paper, we first establish a mathematical model for replay speech and introduce a method for eliminating the negative interference of the channel. Then a novel feature is proposed to detect the replay attacks. To further boost the detection performance, four post-processing methods using normalization techniques are investigated. We evaluate our proposed method on the ASVspoof 2017 dataset. The experimental results show that our approach outperforms the competing methods in terms of detection accuracy. More interestingly, we find that the proposed normalization strategy could also improve the performance of the existing algorithms.

• Journal of Information Technology Applications and Management
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• v.23 no.4
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• pp.127-138
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• 2016

The Korean government has implemented various policies such as establishing new major/department and operating a variety of education programs related with cybersecurity. However, it has not yet been constructed virtuous cycle that can provide appropriate education and training to professionals with the high level and quality. In this study, by surveying and analyzing satisfaction about education and training program aimed at employees in public sector who are in charge of cybersecurity, we suggest the direction of education and training for cybersecurity experts required at the national level.

• Information and Communications Magazine
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• v.33 no.2
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• pp.10-27
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• 2016

Internet of Things defines a large number of diverse entities and services which interconnect with each other and individually or cooperatively operate depending on context, conditions and environments, produce a huge personal and sensitive data. In this scenario, the satisfaction of privacy, security and trust objectives plays a critical role in the success of the Internet of Things. Trust here can be considered as a key property to establish trustworthy and seamless connectivity among entities and to guarantee secure services and applications. The aim of this study is to provide a survey on various trust computation strategies and identify future trends in the field. We discuss trust computation methods under several aspects and provide comparison of the approaches based on trust features, performance, advantages, weaknesses and limitations of each strategy. Finally the research discuss on the gap of the trust literature and raise some research directions in trust computation in the Internet of Things.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.299-300
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• 2017

한국의 지역기반 소규모 기계경비업체들은 고객의 수요는 다변화되어 가는 현실에서 첨단 경비서비스 제공을 위한 시스템의 미비와 전문 인적자원의 부족으로 기업경영의 위기에 봉착했다. 이에 지역기반 소규모 기계경비업체들의 혁신적 생존전략 모색방안의 일환으로 관제업무 아웃소싱 전략이 대두되었다. 기계경비 관제업무 아웃소싱 전략은 관제업무의 일부 또는 특정부분을 전문용역업체에 위탁하는 것으로 첨단 관제시스템과 전문관제요원을 보유하고 관제업무를 대행해 주는 아웃소싱기업의 전문성을 최대한 이용할 수 있는 장점이 있으나, 통제와 보안의 문제, 비용 상승과 계약종결의 문제 및 내부 전문기술의 축적기회 상실 등의 산재한 선결과제도 있다.

• Journal of Information Technology Applications and Management
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• v.28 no.6
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• pp.87-95
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• 2021

Recently interest for air pollution is gradually increasing. However, according to the environmental assessment of air quality, the level of air pollution in the nation is quite serious, and air pollutants measuring facilities are also not enough. In this paper, a secure air pollutants sensor system based low power wireless communication is designed and implemented. The proposed system is composed of three parts: air pollutants measuring sensors module, LoRa-based data transmission module, and monitoring module. In the air pollutants measuring module, the MSP430 board with six big air pollutants measuring sensors are used. The air pollutants sensing data is transmitted to the control server in the monitoring system using LoRa transmission module. The received sensing data is stored in the database of the monitoring system, and visualized in real-time on the map of the sensor locations. The implemented air pollutant sensor system can be used for measuring the level of air quality conveniently in our daily lives.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.710-713
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• 2011

스마트폰의 이용자가 최근 급증하고 있다. 그에 반응하듯 많은 기업들은 기존의 서비스 외에도 스마트폰을 이용해 사용할 수 있는 서비스들을 시작하고 있고, 기존의 모바일로 불가능했던 작업들을 장소와 시간에 구애받지 않고 가능케 되었다. 이처럼 스마트폰의 이용인구가 급격히 증가하고 관련 컨텐츠들이 봇물 쏟아지듯 넘쳐나면서 개인정보 유출이나 악성코드로 인한 보안 사고도 급격히 늘고 있다. 본 논문에서는 스마트폰에 악영향을 미치는 악성코드에 대해 간단히 살펴보고, 악성코드가 쉽게 보안체계를 무너뜨릴 수 있게 만드는 스마트폰의 보안 위협요소 대하여 알아본다. 또 현재 사용되고 있는 대응 방안은 무엇이 있는지, 그리고 향후에 이러한 악성코드들과 위협요소를 줄이는 방법, 또는 대응 전략에 대하여 연구하였다. 이러한 연구는 스마트폰 보안 사고를 줄이거나 사전에 예방하고, 더 나은 스마트폰 사용 환경을 제공할 것이다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.447-448
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• 2020

본 논문에서는 스마트 자동차를 외부에서 제어할 수 있는 원격접속의 보안성을 강화할 수 있는 방안을 제안한다. 다양한 자동차 제조사들이 물리적인 자동차 구동에서 나아가 정보통신기술을 접목하여 운전자에게 다양한 편의성을 제공하고 있다. 정보통신기술을 이용해 자동차의 기능이 증가하는 만큼 정보시스템의 취약성을 이용해 외부의 비인가자에 의한 침입이 이루어질 수 있는 취약성 또한 증대하며, 자동차의 경우 이러한 위협이 주행 중 발생 시 운전자의 생명까지 위협할 수 있는 매우 위험한 상황이 발생할 수 있다. 이에 외부로부터 비인가자의 접근을 차단할 수 있는 방안을 기존 정보통신시스템 보안 기법을 접목하여 스마트 자동차의 안전한 운행이 가능할 수 있도록 한다. 본 논문에서는 기존 정보통신시스템에서 활용 중인 보안 방안을 통하여 제안하는 스마트 자동차 원격접근 제어 정책이 기존의 스마트 자동차 정보보안 정책에 비해 보안성 향상 면에서 더 우수함을 보인다.

• Journal of Information Technology Applications and Management
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• v.30 no.6
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• pp.113-142
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• 2023

As society becomes more digital, the need for digital forensics experts are gradually increasing. It is necessary to establish a training policy that reflects the special characteristics of digital forensics personnel. Although there are fragmented policies for digital forensics-related systems and human resources training in academia, it is an urgently necessary to establish a systematic and long-term policy to foster digital forensics experts. This study suggests curriculum of digital forensic based on the importance ranking among forensic subjects. The importance ranking can be decided by forensic experts. This study can be used as policy data to foster diverse talent that can effectively meet the increasing demand for digital forensics talent. The systematic curriculum proposed in this study is a practical curriculum at the undergraduate level and can be suitable for university level

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.2
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• pp.478-493
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• 2024

In this paper, the Mixed Integer Linear Programming (MILP) model is improved for searching differential characteristics of block cipher Midori-64, and 4 search strategies of differential path are given. By using strategy IV, set 1 S-box on the top of the distinguisher to be active, and set 3 S-boxes at the bottom to be active and the difference to be the same, then we obtain a 5-round differential characteristics. Based on the distinguisher, we attack 12-round Midori-64 with data and time complexities of 2⁶³ and 2^103.83, respectively. To our best knowledge, these results are superior to current ones.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.574-588
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• 2009

Although much research has been conducted in the area of authentication in wireless networks, vehicular ad-hoc networks (VANETs) pose unique challenges, such as real-time constraints, processing limitations, memory constraints, frequently changing senders, requirements for interoperability with existing standards, extensibility and flexibility for future requirements, etc. No currently proposed technique addresses all of the requirements for message and entity authentication in VANETs. After analyzing the requirements for viable VANET message authentication, we propose a modified version of TESLA, TESLA++, which provides the same computationally efficient broadcast authentication as TESLA with reduced memory requirements. To address the range of needs within VANETs we propose a new hybrid authentication mechanism, VANET authentication using signatures and TESLA++ (VAST), that combines the advantages of ECDSA signatures and TESLA++. Elliptic curve digital signature algorithm (ECDSA) signatures provide fast authentication and non-repudiation, but are computationally expensive. TESLA++ prevents memory and computation-based denial of service attacks. We analyze the security of our mechanism and simulate VAST in realistic highway conditions under varying network and vehicular traffic scenarios. Simulation results show that VAST outperforms either signatures or TESLA on its own. Even under heavy loads VAST is able to authenticate 100% of the received messages within 107ms. VANETs use certificates to achieve entity authentication (i.e., validate senders). To reduce certificate bandwidth usage, we use Hu et al.'s strategy of broadcasting certificates at fixed intervals, independent of the arrival of new entities. We propose a new certificate verification strategy that prevents denial of service attacks while requiring zero additional sender overhead. Our analysis shows that these solutions introduce a small delay, but still allow drivers in a worst case scenario over 3 seconds to respond to a dangerous situation.