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