• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.2204-2220
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• 2011

Without providing a proper security measure to the handover procedure in Mobile WiMAX, several security attacks can be mounted. Even though security schemes have been previously proposed for this purpose, they are still vulnerable to several security attacks due to fatal design flaws. A newly proposed security scheme in this paper is based on the framework of authentication domain and concept of handover ticket. A method of establishing security associations within the authentication domain is proposed, and a lightweight security measure to protect the management messages associated with the handover is also proposed. Especially, using the handover ticket, the new security scheme can defend against a Redirection Attack arising from a compromised base station. The new security scheme is comparatively analyzed with the previous security schemes in terms of Replay, Session Hijacking, Man-In-The-Middle, and Redirection attacks.

• 한국멀티미디어학회논문지
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• 제19권1호
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• pp.41-50
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• 2016

Moblie device based financial services are vulnerable to social engineering attacks because of the display screen of mobile devices. In other words, in the case of shoulder surfing, attackers can easily look over a user's shoulder and expose his/her password. To resolve this problem, a colour-based secure keyboard solution has been proposed. However, it is inconvenient for genuine users to verify their password using this method. Furthermore, password colours can be exposed because of fixed keyboard colours. Therefore, we propose a secure mobile authentication method to provide advanced functionality and strong privacy. Our authentication method is robust to social engineering attacks, especially keylogger and shoulder surfing attacks. According to the evaluation results, our method offers increased security and improved usability compared with existing methods.

• Journal of Multimedia Information System
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• 제7권1호
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• pp.45-54
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• 2020

This paper presented a brief introduction along with various wireless standards which provide an interactive way of interaction among the vehicles and provides effective communication in VANET. Security issues such as confidentiality, authenticity, integrity, availability and non-repudiation, which aims to secure communication between vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I). A detailed discussion and analysis of various possible attacks based on security services are also presented that address security and privacy concern in VANETs. Finally a general analysis of possible challenges is mentioned. This paper can serve as a source and reference in building the new technique for VANETs.

• Journal of Information Processing Systems
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• 제7권4호
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• pp.691-706
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• 2011

Since security and privacy problems in RFID systems have attracted much attention, numerous RFID authentication protocols have been suggested. One of the various design approaches is to use light-weight logics such as bitwise Boolean operations and addition modulo $2^m$ between m-bits words. Because these operations can be implemented in a small chip area, that is the major requirement in RFID protocols, a series of protocols have been suggested conforming to this approach. In this paper, we present new attacks on these lightweight RFID authentication protocols by using the Gr$\ddot{o}$bner basis. Our attacks are superior to previous ones for the following reasons: since we do not use the specific characteristics of target protocols, they are generally applicable to various ones. Furthermore, they are so powerful that we can recover almost all secret information of the protocols. For concrete examples, we show that almost all secret variables of six RFID protocols, LMAP, $M^2AP$, EMAP, SASI, Lo et al.'s protocol, and Lee et al.'s protocol, can be recovered within a few seconds on a single PC.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.1-10
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• 2021

The purpose of the study is to contribute to the positive development of blockchain technology by providing data to examine security vulnerabilities and threats to blockchain-based services and review countermeasures. The findings of this study are as follows. Threats to the security of blockchain-based services can be classified into application security threats, smart contract security threats, and network (P2P) security threats. First, application security threats include wallet theft (e-wallet stealing), double spending (double payment attack), and cryptojacking (mining malware infection). Second, smart contract security threats are divided into reentrancy attacks, replay attacks, and balance increasing attacks. Third, network (P2P) security threats are divided into the 51% control attack, Sybil attack, balance attack, eclipse attack (spread false information attack), selfish mining (selfish mining monopoly), block withholding attack, DDoS attack (distributed service denial attack) and DNS/BGP hijacks. Through this study, it is possible to discuss the future plans of the blockchain technology-based ecosystem through understanding the functional characteristics of transparency or some privacy that can be obtained within the blockchain. It also supports effective coping with various security threats.

• International Journal of Computer Science & Network Security
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• 제24권4호
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• pp.155-162
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• 2024

Anonymity online has been an ever so fundamental topic among journalists, experts, cybersecurity professionals, corporate whistleblowers. Highest degree of anonymity online can be obtained by mimicking a normal everyday user of the internet. Without raising any flags of suspicion and perfectly merging with the masses of public users. Online Security is a very diverse topic, with new exploits, malwares, ransomwares, zero-day attacks, breaches occurring every day, staying updated with the latest security measures against them is quite expensive and resource intensive. Network security through anonymity focuses on being unidentifiable by disguising or blending into the public to become invisible to the targeted attacks. By following strict digital discipline, we can avoid all the malicious attacks as a whole. In this paper we have demonstrated a proof of concept and feasibility of securing yourself on a network by being anonymous.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.475-478
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• 2012

사이버 공간의 중요성이 커지고 그에 대한 의존성이 높아지면서 부수적으로 산업기밀유출, 사이버 테러, 개인정보유출의 문제 뿐 아니라 국가 간의 사이버 전쟁의 우려가 커지는 등 사이버 공간의 잠재적 위험성과 그에 따른 피해범위와 규모도 커지고 있는 실정이다. 그러므로 이에 대한 대비는 국가의 안보와 직결될 만큼 중요성이 커지고 있다. 따라서 정보보호체계의 확립이 시급하며 사이버 피해에 대한 체계적 이해가 필요하다. 이를 위하여 피해규모 및 피해액 추정 방법을 정리하고 이를 바탕으로 사이버 보호 대책을 수립해야 한다. 사이버보호의 경제적 효과는 사이버 보호 정책을 수립하는 기초적인 자료가 될 것이다. 본 연구에서는 사이버 피해의 체계적 이해를 바탕으로 사이버 보호의 경제적 효과에 대한 합리적인 추정방안을 연구하고자 한다.

• 한국정보통신학회논문지
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• 제10권12호
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• pp.2193-2201
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• 2006

이동통신 환경과 관련하여 프라이버시 측면에서 모바일 이용자들의 현 위치와 행적 노출에 대한 문제를 해결하기 위해 Kesdogan과 Pfitzmann[1,2,3]은 TP(Temporary Pseudonym)라는 임시 익명 아이디를 이용한 방법들을 제안하였으며, 그 후 우리는 [4]에서 네트워크 제공자 측의 능동적인 공격들로부터 모바일 이용자들을 보호할 수 있는 보다 개선된 방법을 제안한 바 있다. 그러나 우리가 기존에 제안한 프로토콜은 이동 사용자가 홈도메인 내에 위치 할 경우만을 가정한 것이다. 본 논문에서는 이를 보다 확장하여 이동 사용자가 홈도메인 내에서 원격지에 있는 방문 도메인으로 이동할 경우에 사용자의 프라이버시를 보호할 수 있는 새로운 이동 착호 프로토콜을 제안하고 그것의 안전성에 대해 분석하고자 한다.

• ETRI Journal
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• 제33권6호
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• pp.935-944
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• 2011

As a growing number of individuals are exposed to surveillance cameras, the need to prevent captured videos from being used inappropriately has increased. Privacy-related information can be protected through video encryption during transmission or storage, and several algorithms have been proposed for such purposes. However, the simple way of evaluating the security by counting the number of brute-force trials is not proper for measuring the security of video encryption algorithms, considering that attackers can devise specially crafted attacks for specific purposes by exploiting the characteristics of the target video codec. In this paper, we introduce a new attack for recovering contour information from encrypted H.264 video. The attack can thus be used to extract face outlines for the purpose of personal identification. We analyze the security of previous video encryption schemes against the proposed attack and show that the security of these schemes is lower than expected in terms of privacy protection. To enhance security, an advanced block shuffling method is proposed, an analysis of which shows that it is more secure than the previous method and can be an improvement against the proposed attack.

• 한국융합학회논문지
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• 제9권11호
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• pp.75-81
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• 2018

블록체인 내의 모든 트랜잭션이 공개되기 때문에 익명성과 프라이버시 문제는 중요해지고 있다. 공개 블록체인은 사용자 대신 공개키 주소를 사용하여 익명성을 보장하는 것처럼 보이지만 트랜잭션 그래프를 기반으로 다양한 기법을 통해 추적함으로써 익명성을 약화시킬 수 있다. 본 논문에서는 블록체인 환경에서 익명성과 프라이버스를 보호하기 위하여 다양한 보안 기법을 융합하여 사용자의 추적을 어렵게 하는 기법을 제안한다. 제안 기법은 k-anonymity 기술, 믹싱 기술, 은닉서명, 다단계 기법, 램덤 선택기법, 영지식 증명 기법 등을 융합하여 인센티브 및 기여자의 참여를 통해 익명성과 프라이버시를 보호한다. 성능 분석을 통해 제안기법은 기여자의 수가 공모자의 수보다 많은 환경에서는 공모를 통한 프라이버시 및 익명성 훼손이 어렵다는 것을 보였다.