Routing for Enhancing Source-Location Privacy in Wireless Sensor Networks of Multiple Assets

Tscha, Yeong-Hwan The Korea Institute of Information and Commucation 2009 Journal of communications and networks Vol.11 No.6

In wireless sensor networks, a node that reports information gathered from adjacent assets should relay packets appropriately so that its location context is kept private, and thereby helping ensure the security of the assets that are being monitored. Unfortunately, existing routing methods that counter the local eavesdropping-based tracing deal with a single asset, and most of them suffer from the packet-delivery latency as they prefer to take a separate path of many hops for each packet being sent. In this paper, we propose a routing method, greedy perimeter stateless routing-based source-location privacy with crew size w (GSLP-w), that enhances location privacy of the packet-originating node (i.e., active source) in the presence of multiple assets. GSLP-w is a hybrid method, in which the next-hop node is chosen in one of four modes, namely greedy, random, perimeter, and retreat modes. Random forwarding brings the path diversity, while greedy forwarding refrains from taking an excessively long path and leads to convergence to the destination. Perimeter routing makes detours that avoid the nodes near assets so that they cannot be located by an adversary tracing up the route path. We study the performance of GSLP-w with respect to crew size w (the number of packets being sent per path) and the number of sources. GSLP-w is compared with phantom routing-single path (PR-SP), which is a notable routing method for source-location privacy and our simulation results show that improvements from the point of the ratio of safety period and delivery latency become significant as the number of source nodes increases.

컴퓨터 네트워크 : 이동 호스트들간의 경제성있는 통신을 위한 새로운 루팅 프로토콜

차영환(Tscha Yeong Hwan) 한국정보처리학회 1995 정보처리학회논문지 Vol.2 No.3

본 논문은 이동 호스트(mobile host)를 수용하는 컴퓨터 네트워크 상에 있어 이동 호스트간의 경제성 있는 통신을 지원하는 메세지 루팅 프로토콜에 관한 것이다. 제안된 루팅 프로토콜은 이동 호스트의 위치 이동에 따른 위치 정보의 등록을 담당하는 위치 등록 프로토콜과 이동 호스트로의 신뢰성있는 메세지 전달을 수행하는 메세지 전달 프로토콜로 구성된다. 제안 프로토콜의 주요 특성과 동작 절차를 제안하고, 기존의 대표적인 프로토콜과의 비교를 통해 제안된 프로토콜이 기능적인 측면에서는 물론 메세지 루팅시 수반되는 통신 비용(메세지 수)에 있어서도 개선되었음을 보였다. This paper is concerned with a routing protocol for cost-effective communications between mobile hosts on computer networks in which mobile hosts can move freely their physical positions. The proposed routing protocol consists of two protocols : one is called location registration protocol performing registration of the location information as the mobile host does move; the other one is called message transfer protocol which actually delivers a message to the destination mobile host. The detailed protocol's operational behavior and major characteristics are presented. And it is shown that out protocols are superior to previous ones, in terms of the communication cost(i.e., number of message) required for routing a message, and are functionally improved ones.

Routing for Enhancing Source-Location Privacy in Wireless Sensor Networks of Multiple Assets

Yeonghwan Tscha 한국통신학회 2009 Journal of communications and networks Vol.11 No.6

In wireless sensor networks, a node that reports information gathered from adjacent assets should relay packets appropriately so that its location context is kept private, and thereby helping ensure the security of the assets that are being monitored. Unfortunately, existing routing methods that counter the local eavesdropping-based tracing deal with a single asset, and most of them suffer from the packet-delivery latency as they prefer to take a separate path of many hops for each packet being sent. In this paper, we propose a routing method, greedy perimeter stateless routing-based source-location privacy with crew size w (GSLP-w), that enhances location privacy of the packet-originating node (i.e., active source) in the presence of multiple assets. GSLP-w is a hybrid method, in which the next-hop node is chosen in one of four modes, namely greedy, random, perimeter, and retreat modes. Random forwarding brings the path diversity, while greedy forwarding refrains from taking an excessively long path and leads to convergence to the destination. Perimeter routing makes detours that avoid the nodes near assets so that they cannot be located by an adversary tracing up the route path. We study the performance of GSLP-w with respect to crew size w (the number of packets being sent per path) and the number of sources. GSLP-w is compared with phantom routing-single path (PR-SP), which is a notable routing method for source-location privacy and our simulation results show that improvements from the point of the ratio of safety period and delivery latency become significant as the number of source nodes increases.

On Sensor Network Routing for Cloaking Source Location Against Packet-Tracing

Yeonghwan Tscha 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.3

Most of existing routing methods in wireless sensor networks to counter the local eavesdropping-based packet-tracing deal with a single asset and suffer from the packet-delivery latency as they prefer to take a separate path of many hops for each packet being sent. Recently, the author proposed a routing method, GSLP-w(GPSR-based Source-Location Privacy with crew size w), that enhances location privacy of the packet-originating node(i.e., active source) in the presence of multiple assets, yet taking a path of not too long. In this paper, we present a refined routing(i.e., next-hop selection) procedure of it and empirically study privacy strength and delivery latency with varying the crew size w(i.e., the number of packets being sent per path). It turns out that GSLP-w offers the best privacy strength when the number of packets being sent per path is randomly chosen from the range [1,hs-b/4] and that further improvements on the privacy are achieved by increasing the random walk length TTLrw or the probability prw that goes into random walk(where, hs-b is the number of hops of the shortest path between packet-originating node s and sink b).

정보통신 : 이동 호스트를 위한 개선된 이동성 관리 및 멀티캐스트 프로토콜

차영환(Tscha Yeong Hwan),성현경(Sung Hyeon Kyeong) 한국정보처리학회 1995 정보처리학회논문지 Vol.2 No.1

휴대용 컴퓨터기술과 무선 통신기술 및 컴퓨터망이 통합된 육상이동컴퓨터망(LMCN: Land Mobile Computer Network)의 출현은 시간과 장소에 구속받지않는 궁국적인 컴퓨터통신을 제공할 수 있다. 그러나 LMCN에서는 이동호스트(MH: Mobile Host)의 물리적인 위치이동에 따라 통신망의 연결성(connectivity)이 바뀌게되어 통신망의 연결성 정보를 유지하기위한 통신비용이 요구됨은 물론 메시지의 중복, 손실 및 비순서적 주신이 발생할 수 있다. 이러한 문제점들을 해결하기위해 MH에대한 위치정보의 갱신과 메세지의 멀티캐스트를 위해 flooding 기법을 이용하는 기존의 연구에서는 과중한 통신비용의 부담이 불가피하다. 본 논문에서는 이와같은 문제점들을 야기시키는 flooding 기법을 이용하지않는 새로운 이동성관리 프로토콜과 메세지가 손실없이, 중복되지않고, 순서적으로 수신될 수 있는 멀티캐스트 프로토콜을 제시하였다. 이를 위해 MH의 위치정보를 관리하는 망기능들과 멀티캐스트 관련 기능들을 계층화하였으며, 계층화된 기능들간의 위치등록, 핸드오버 그리고 멀티캐스트 절차를 각기 설계하였다. 기존의 프로토콜과의 통신비용의 비교 분석을 통해 제안된 프로토콜이 보다 경제적임을 보였다. By intergrating technologies for portable computers, radio communications, and computer networking, the Land Mobile Computer Network(LMCN) is supposed to overcome the time and space limitation of present computer communication networks. However, because the MHs(mobile hosts) do move any time, the network connectivity is often changed causing temporarily duplicated, lost, or out-of-sequenced message delivery as well as frequent communications for maintainning the network connectivity. Previous works solved the problems through message flooding, used also in multicasting, resulting in high communication cost(i.e., number of communication messages). In this paper, new protocols for efficient mobility management and multicasting are proposed. The protocols define location update, handover, and multicasting procedure of a MH over a hierarchical LMCN architecture. The protocol specification is presented, and it is shown that the communication cost of the new protocols is superior to the existing ones in terms of the communication cost.

방향성 안테나에 기반을 둔 애드 혹 네트워크를 위한 신뢰성 있는 브로드캐스팅 기법

차영환(Yeonghwan Tscha) 한국정보기술학회 2008 한국정보기술학회논문지 Vol.6 No.6

In this paper we propose a low-cost reliable broadcasting scheme called BSART (Broadcasting with Selected Acknowledgement and Repeated Transmission), designed especially for mobile ad hoc networks which are capable of directional communications using switched beam antenna elements. To alleviate the broadcast storm problem, a phenomena generates heavily redundant messages in broadcasting, a method to control the number of message forwarding nodes performing broadcasting(including the number of antenna elements deployed by these nodes) is taken into account. Recognizing ACK-based reliable transmission usually causes the ACK implosion problem, the repeated transmission without ACK (R-scheme) is applied to the switch element where the number of recipient neighbor nodes is above some particular threshold, otherwise the native ACK-based Acknowledgement (A-scheme) is considered. It is given through simulation that the proposed BSART is capable of controlling the number of message forwarding nodes, as well as the number ACK message incoming into to the forward nodes, and that the message delivery ratio is beyond 90% at nodal speed of 20m/s.

Multi - Log₂N 다중접속 망의 넌블럭킹 조건에 관한 새로운 결과

차영환(Yeonghwan Tscha),이균하(Kyoon Ha Lee) 한국정보과학회 1992 한국정보과학회 학술발표논문집 Vol.19 No.1

본 논문에서는 그 동안 미해결 문제(open problem)들[1-4]로 남아있던 Multi-Log₂N 다중접속 망의 Rearrangeable 넌블럭킹 조건과 Strictly 넌블럭킹 조건을 제시 하였다. 기존의 예측[1,2]과 달리 Multi-Log₂N 다중접속 망의 넌블럭킹 조건들은 Multi-Log₂N 일대일접속 망의 넌블럭킹 조건들과 일치한다는 흥미로운 결과를 얻었다. 본 논문에서 규명된 넌블럭킹 조건들은 물론 SIS(Subconnection-Intersection Set) 정규화된 SIS(Normalized SIS), SIG(Subconnection-Intersection Graph) 및 UMSR(Unified Multiconnection-Segmenting Rule)등은 다중접속 광대역 스위치의 개발은 물론 하나 또는 2개 이상의 스위치 망을 복수개 이용하는 다양한 구조의 다중접속 스위치 망에 있어 유용성있는 기본 자료로 활용될 수 있을 것으로 판단된다.

방향성 안테나에 기반을 둔 이동 애드 혹 네트워크에서의 대체 경로 설정

차영환(Yeonghwan Tscha) 한국멀티미디어학회 2007 멀티미디어학회논문지 Vol.10 No.9

근원지 위치 보호 라우팅 기법 GSLP의 확장에 관한 연구

차영환(Yeonghwan Tscha) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.1

In wireless sensor networks, it may be easy to repeatedly eavesdrop the packet transmission signal and finally to identify the packet-originating node(i.e., source). GSLP(GPSR-based Source-Location Privacy) was proposed as a routing scheme that countermeasures against such tracing and also that relays packets appropriately so that other assets locations are kept private. Through simulations, in this paper, the source-location privacy level(safety period) of GSLP was evaluated by comparing with Phantom routing for the case that a source node changes and the other case where several sources transmit their packets simultaneously. In the former, GSLP kept at a certain privacy level as the number of sources needed location-privacy increases, and in the latter, the privacy level of GSLP roughly doubled that of Phantom. In case that multiple adversaries trace their own sources concurrently, GSLP showed low delivery latency and high privacy level provided that each source sends its packets to a randomly selected base station rather than to a near or far-off one.

센서 네트워크에서 낮은 전달 지연으로 근원지 위치 기밀을 강화하는 라우팅

차영환(Yeonghwan Tscha) 한국통신학회 2008 韓國通信學會論文誌 Vol.33 No.8B

센서 네트워크에 있어서 정보 전송 노드인 근원지의 위치를 악의적 추적자로부터 보호하기 위해 길이가 긴 경로를 통해 단일 메시지를 전송하는 라우팅에서는 전달 지연이 길어지는 단점이 있다. 본 논문에서는 전송 메시지가 사전에 주어진 경우, 근원지 위치를 보호하면서 최소 비용의 단일 경로를 이용하여 이들을 목적지로 전달하는 문제는 NP-complete 임을 보인다. 이러한 양 극단의 절충 방안이라 할 수 있는 경로 당 ω개의 메시지들을 전송하도록 하여 근원지의 위치 보호 능력을 높이면서도 전달 지연을 저감시키는 라우팅 프로토콜 GSLP-ω (GPSR-based Source Location Privacy with crew size ω)를 제안한다. 평가 기준으로는 목적지와의 최단 경로의 홉 수를 기준으로 정규 안전 기간(NSP: Normalized Safety Period)과 정규 전달 지연(NDL: Normalized Delivery Latency)을 고려한다. 평균 차수(degree)가 8인 노드 50,000개로 구성되는 네트워크 토폴로지 100개를 생성하여 측정한 결과 제안된 GSLP-ω는 GSLP-ω의 초기 버전인 GSLP와 기존의 대표적인 근원지 위치 보호 라우팅 프로토콜인 PR-SP(Phantom Routing - Single Path)보다 더 높은 안전 기간을 보였다. 전달 지연에서는 GSLP-ω가 PR-SP보다 높으나 GSLP 보다는 낮은 것으로 나타났다. Most of routing schemes that protect the source's location from a malicious attacker usually make use of a path of a long length per message for the sake of lengthening the safety period. The biggest problem to such approaches is taking a very long latency in transferring messages to the destination. In this paper we show the problem to find the least-cost single path that is enough to keep the source-location always secure from the attacker, provided that it is used for the delivery of a set of messages given in priori, is NP-complete. Consequently we propose a routing protocol GSLP-w(GPSR-based Source-Location Privacy with crew size ω) that is a trade-off between two extreme approaches. The advantage of GSLP-ω lies in its enhanced safety period for the source and its lowered delivery latency in messaging. We consider NSP(Normalized Sefety Period) and NDL(Normalized Delivery Latency), measured in terms of the least number of hops to the destination, to achieve tangible interpretation of the results. We ran a simulation to confirm our claim by generating 100 topologies of 50,000 nodes with the average number of neighbors being 8. The results show that GSLP-ω provides more enhanced NSP compared to other protocols GSLP, an earlier version of GSLP-ω, and PR-SP(Phantom Routing - Single Path), the most notable existing protocol for the source-location privacy, and less NDL than that of GSLP but more than that of PR-SP.