Secure Local Data Aggregation andDelay Tolerant Dissemination in VANETs

Presented byCesar Ghali Sky Faber Kyle Benson Quan Nguyen

University of California, Irvine

CS 234 – June, 2012

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• Distributed event detection in Vehicular Adhoc NETworkso Interested in detecting vehicle crash eventso Collision will affect both nearby vehicles and

vehicles approaching the site• Other vehicles may be present during such an

evento May flood the wireless channel with crash data

Introduction

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• Minimize the amount of power consumed by radio transmissionso Extend the battery lifeo Reduce communication overhead

Data Aggregation

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• Minimum spanning trees (MST)o Maximize the degreeo Maximize the number of hops

• Leader election algorithmo Address the collision transmission problem in

wireless networks• Time-constrained data transmission

o Ensure that all data eventually reaches the sink

Data Aggregation - Solutions

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• Flow updatingo Broadcast- and gossip-basedo Exploit the symmetry of the network flows

• Hierarchical aggregationo Based on the distance form the origin

Data Aggregation - Solutions

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• Broadcast data to the local subset network• Locality• Quickly• Efficiently

Data Dissemination

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• Flash disseminationo Broadcast as fast as possibleo Not scalable

• CREWo Gossip-basedo Prevent receiving multiple copies of the same

messageo Scalable

Data Dissemination - Solutions

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• Jamming attacko Interfere the radio channel

• Hidden vehicleo Adversary pretend to be in better position for

broadcasto Results: stop broadcasting

Security Concerns

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• Wormhole attacko Tunneling message from area A to area B using

fast external channelo Authentic messages sento Trick vehicles in area B

• Sybil attacko Multiple fake identitieso Fake positions

Security Concerns

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• Design a protocol for event detection in VANETso Initial event detectiono Dissemination

• Simulation on NS3

Contributions

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• Authentication of original event data• Based on flash dissemination• Built on top of a graph topology• Multiple observers agreement• Data integrity• Non repudiation• Designed for quick dissemination for most likely

affected vihecle

Algorithm and System Design

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Evaluation

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Conclusion