• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권7호
• /
• pp.3421-3437
• /
• 2018

With the enlargement of wireless technology, vehicular ad-hoc networks (VANETs) are rising as a hopeful way to realize smart cities and address a lot of vital transportation problems such as road security, convenience, and efficiency. To achieve data confidentiality, integrity and authentication applying lightweight cryptosystems is widely recognized as a rather efficient approach for the VANETs. The Khudra cipher is such a lightweight cryptosystem with a typical Generalized Feistel Network, and supports 80-bit secret key. Up to now, little research of fault analysis has been devoted to attacking Khudra. On the basis of the single nibble-oriented fault model, we propose a differential fault analysis on Khudra. The attack can recover its 80-bit secret key by introducing only 2 faults. The results in this study will provides vital references for the security evaluations of other lightweight ciphers in the VANETs.

• 디지털산업정보학회논문지
• /
• 제14권1호
• /
• pp.27-34
• /
• 2018

Various messages generated in vehicles are transmitted based on the wireless telecommunication which is a core technology of vehicle to everything (V2X). However, the hackers attack them upon penetration to the system and network to cause the generation of users' inconveniences for vehicular communication. Moreover, huge damage could be occurred in terms of physical and materialistic areas if the users in the vehicles were attacked in the communication environment. Therefore, this study was to design the safe communication protocol using hash tree technique in the V2X environments. Using hash tree technique, processes of issuing certificate and registration and communication protocol were designed, and safety analysis was performed on the attacking technique which is occurred in the existing vehicles. Approximately 62% of decrease in the capacity analysis was found upon comparative analysis of telecommunication processes with the system to issue the certificate which is used in the existing vehicles.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권12호
• /
• pp.6121-6144
• /
• 2019

Numerous privacy-preserving authentication schemes have been proposed but vehicular ad hoc networks (VANETs) still suffer from security and privacy issues as well as computation and communication overheads. In this paper, we proposed a robust conditional privacy-preserving authentication scheme based on pseudonym root with cuckoo filter to meet security and privacy requirements and reduce computation and communication overheads. In our proposed scheme, we used a new idea to generate pseudonyms for vehicles where each on-board unit (OBU) saves one pseudonym, named as "pseudonym root," and generates all pseudonyms from the same pseudonym. Therefore, OBU does not need to enlarge its storage. In addition, the scheme does not use bilinear pairing operation that causes computation overhead and has no certification revocation list that leads to computation and communication overheads. The proposed scheme has lightweight mutual authentication among all parties and just for once. Moreover, it provides strong anonymity to preserve privacy and resists ordinary attacks. We analyzed our proposed scheme and showed that it meets security and privacy requirements of VANETs and is more efficient than traditional schemes. The communication and computation overheads were also discussed to show the cost-effectiveness of the proposed scheme.

• ETRI Journal
• /
• 제41권6호
• /
• pp.703-714
• /
• 2019

Many use cases have been presented on providing convenience and safety for vehicles employing wireless access in vehicular environments and long-term evolution communication technologies. As the 70-MHz bandwidth in the 5.9-GHz band is allocated as an intelligent transportation system (ITS) service, there exists the issue that vehicular communication systems should not interfere with each other during their usage. Numerous studies have been conducted on adjacent interfering channels, but there is insufficient research on vehicular communication systems in the ITS band. In this paper, we analyze the interference channel performance between communication systems using distribution functions. Two types of scenarios comprising adjacent channel interference are defined. In each scenario, a combination of an aggressor and victim network is categorized into four test cases. The minimum requirements and conditions to meet a 10% packet error rate are analyzed in terms of outage probability, packet error rate, and throughput for different transmission rates. This paper presents an adjacent channel interference ratio and communication coverage to obtain a satisfactory performance.

• Journal of Information Processing Systems
• /
• 제11권3호
• /
• pp.465-482
• /
• 2015

IEEE 802.11p is a standard MAC protocol for wireless access in vehicular environments (WAVEs). If a packet collision happens when a safety message is sent out, IEEE 802.11p chooses a random back-off counter value in a fixed-size contention window. However, depending on the random choice of back-off counter value, it is still possible that less important messages are sent out first while more important messages are delayed longer until sent out. In this paper, we present a new scheme for safety message scheduling, called the enhanced message priority mechanism (EMPM). It consists of the following two components: the benefit-value algorithm, which calculates the priority of the messages depending on the speed, deceleration, and message lifetime; and the back-off counter selection algorithm, which chooses the non-uniform back-off counter value in order to reduce the collision probability and to enhance the throughput of the highly beneficial messages. Numerical results show that the EMPM can significantly improve the throughput and delay of messages with high benefits when compared with existing MAC protocols. Consequently, the EMPM can provide better QoS support for the more important and urgent messages.

• 전자공학회논문지
• /
• 제49권11호
• /
• pp.132-138
• /
• 2012

VANET(Vehicular Ad-hoc Network)을 지원하기 위해 IEEE 802.11p 규격이 표준화 진행중에 있다. 802.11 MAC 프로토콜은 전송률에 관계없이 모든 노드들에 동일한 확률의 채널 획득 기회를 부여하므로, 전송률이 낮은 노드가 상대적으로 채널 점유시간이 길어져서 전송률이 높은 노드도 전송률이 낮은 노드의 전송률로 하향 평준화되는 문제와, 노드가 많아질 경우 충돌 확률이 높아지는 문제가 있다. 본 논문에서 제안하는 알고리듬은 일단 채널을 획득한 단말기가 다른 노드와의 채널획득 경쟁의 우위를 일정 기간 유지하는 알고리듬에, 현재 전송률에 따라 적절히 연속전송 한계값을 정하는 TXOP 개념을 더했다. CW의 폭을 표준보다 더 넓게 설정여 효과적으로 충돌을 회피하면서도 대기시간을 최소화하면서 또한 채널 점유 시간에 따라 연속전송 한계값을 다르게 정하는 방법을 통해 전체 네트워크의 향상을 보이고 있다.

• 한국통신학회논문지
• /
• 제40권11호
• /
• pp.2252-2260
• /
• 2015

본 논문에서는 상용 차량에 많이 쓰이는 GNSS, 비전 센서, 레이더 센서를 이용한 협력 항법시스템을 제안하였다. 기존의 무선신호(예:UWB) 기반의 협력 항법시스템 (Hybrid-Sum Product Algorithm over Wireless Network, H-SPAWN)을 바탕으로 하여 무선신호 방식 대신 비전 센서와 레이더 센서를 모델링하여 알고리즘을 구성하였다. 모의실험을 통해, 사용하는 센서에 따른 성능을 비교분석하였으며, 특히 레이더 센서를 사용할 시 다른 두 센서(비전, UWB) 대비 최대 50%의 오차저감 효과를 보임을 확인하였다. 따라서 상용 차량에 쓰이는 센서 기반의 협력 항법시스템은 기존의 협력항법 시스템의 정확도를 향상시키면서 적용비용을 줄일 수 있는 기술이 될 수 있을 것이다.

• 한국통신학회논문지
• /
• 제36권5B호
• /
• pp.464-470
• /
• 2011

V2V(Vehicle-to-Vehicle)는 VANET(Vehicular Ad-hoc Network)의 한 형태로 높은 이동성과 빈번한 토폴로지 변화로 인하여 링크 단절 문제를 야기 시킨다. 이러한 문제를 해결하기 위하여 그리디 포워딩 (greedy forwarding)과 같은 지리 기반 라우팅 프로토콜이 제안되었다. 그러나 그리디 포워딩 방식은 자신의 전송 범위 안에 속해 있는 노드들 중 목적지 노드와 가장 가까운 노드를 다음 전송 노드로 선정하기 때문에 교차로 및 차량의 진행 변화가 많은 도심 환경에서는 많은 문제점이 발생한다. 이러한 문제를 해결하기 위하여 본 논문에서는 2-hop 이웃 노드의 유/무와 도로의 특성을 고려한 GPUR(Greedy Perimeter Urban Routing) 알고리즘을 제안한다. ns-2를 사용한 성능 평가 결과 도심 환경에서 GPUR 알고리즘이 기존의 라우팅 프로토콜에 비해 경로 설정 오류 문제와 로컬 맥시멈(local maximum)에 직면할 확률을 현저히 감소시킴을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권12호
• /
• pp.2272-2293
• /
• 2011

Communication technology of future networks is predicted to provide a large variety of services including WiFi service in vehicular network. In this paper, we assume that vehicles are embedded with WiMAX antenna and in-vehicle terminals receive WiMAX traffic through WiFi interface. This assumption will impose severe performance degradation due to interference among mobile BSSs when WiFi access points (APs) are densely located. Existing interference avoidance techniques cannot properly resolve the above problems and do not cope with dynamically moving vehicular scenario since they focus only on the fixed network topology. In this paper, we propose a mobility-aware interference avoidance scheme for WiFi services. The proposed scheme computes the interference duration by exploiting mobility vector and location information of neighboring APs. If the interference duration is not negligible, our scheme searches for another channel in order to avoid interference. However, if the interference duration is negligible, our scheme continues to use the channel to reduce switching overhead. To measure the effectiveness of the proposed scheme against other existing techniques, we evaluated performance by using OPNET simulator. Through the simulation, we obtained about 60% reduction in the maximum interference frequency and about 67% improvement in throughput. Furthermore, our scheme provides fair channel usage.

• 정보보호학회지
• /
• 제19권1호
• /
• pp.134-142
• /
• 2009

VANET(Vehicular Ad-hoc Network)은 MANET(Mobile Ad-hoc Network)의 한 형태로, 다수의 차량들이 무선통신을 이용하여 차량 간 통신 또는 차량과 노변장치(Roadside Equipment) 간의 통신을 제공하는 차세대 네트워킹 기술이다. VANET은 주로 사고를 예방하기 위해 사용된다. VANET은 사람의 안전과 생명을 보호하는 중요한 역할을 하기 때문에 보안을 반드시 고려해야 한다. 본 고에서는 VANET에서의 보안과 관련된 고려사항 및 제약사항과 위협을 서술하고 VANET이 만족해야 할 보안요구사항에 대해 분석한다.