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Where Are You From? Confusing Location Distinction Using Virtual Multipath Camouflage

Where Are You From? Confusing Location Distinction Using Virtual Multipath Camouflage. Song Fang, Yao Liu. Wenbo Shen , Haojin Zhu. Location d istinction. Content. Virtual m ultipath attacks. Defense. Experiment. Summary.

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Where Are You From? Confusing Location Distinction Using Virtual Multipath Camouflage

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  1. Where Are You From? Confusing Location Distinction Using Virtual Multipath Camouflage Song Fang, Yao Liu WenboShen, Haojin Zhu

  2. Locationdistinction Content • Virtualmultipathattacks • Defense • Experiment • Summary

  3. Detect a wireless user’s location change, movement or facilitate location-based authentication. Goaloflocation distinction

  4. Applications: • Wirelesssensornetwork:Locationdistinctioncanpreventanunauthorizedpersonfrommovingthesensorsawayfromtheareaofinterest

  5. Example1:

  6. Example1(Cont’d):

  7. Wirelesssensornetwork:LocationdistinctioncanpreventanunauthorizedpersonfrommovingthesensorsawayfromtheareaofinterestWirelesssensornetwork:Locationdistinctioncanpreventanunauthorizedpersonfrommovingthesensorsawayfromtheareaofinterest • Sybilattack:Locationdistinctioncandetectidentitiesoriginatedfromthesamelocation Applications:

  8. Example2:

  9. Example2 (Cont’d): Fromthe samelocation X

  10. Applications: • Wirelesssensornetwork:Locationdistinctioncanpreventanunauthorizedpersonfrommovingthesensorsawayfromtheareaofinterest • Sybilattack:Locationdistinctioncandetectidentitiesoriginatedfromthesamelocation • RFID:Provideawarningandfocus resourcesonmovingobjects (LocationDistinction[MobiCom’07]).

  11. Example3: Move Control

  12. Example3: Move Control

  13. Spatialuncorrelationproperty Existing ways torealizelocation distinction Change Wirelesschannelcharacteristics Locationchange Attack:Generate“arbitrary”characteristic FAIL!!

  14. Multipatheffect • Component response: • Characterizes the distortion that each path has on the multipath component • Multipath components Channel impulse response: The superposition of all component responses Received signal Transmitted signal

  15. Channel impulse response • The channel impulse response changes as the receiver or the transmitter changes location • Calculate the difference Channel impulse responses can be utilized to provide location distinction.

  16. Training sequence based channel estimation Training Sequence x Training Sequence x ChannelEstimation x y x Estimator Channel Impulse response h

  17. Rewrite the received symbols ChannelEstimation (Cont’d) AToeplitzmatrix • Least-square (LS) estimator

  18. Locationdistinction Content • Virtualmultipathattacks • Defense • Experiment • Summary

  19. Example:Creatingavirtualmultipath

  20. AttackOverview:delay-and-sumprocess. The attacker’s aims to make Theithdelayedsignalcopy Virtual channel impulse response

  21. Send the aggregatedsignaltotherealmultipathchannel TechnicalChallenge:Obtainingtheweights

  22. Locationdistinction Content • Virtualmultipathattacks • Defense • Experiment • Summary

  23. Defendingagainsttheattack:Addingahelper

  24. Defendingagainsttheattack:Addingahelper In this case, the attacker must know the real channel impulse response between herself and the helper.

  25. Defendingagainsttheattack:Addingahelper • ForReceiver: • ForHelper:

  26. Attackerswithhelper To fool both the receiver and the receiver’s helper, the attacker needs to know the real channel impulse responses: Unknown Fail to launch attacks Can be set passively: it doesn’t actively send out wireless signals to channel

  27. Locationdistinction Content • Virtualmultipathattacks • Defense • Experiment • Summary

  28. Experimentfloorplan • Transmitter: RX • Receiver:10locations • Eachnode:aUSRPconnectedwithaPC • Trials: 100perlocation • Multipath:L=5

  29. Randomlychosenchannelimpulseresponse ExampleattacksI Euclidean distance:

  30. Recover another channelimpulseresponseinanotherbuilding(CRAWDADdataset[1]) ExampleattacksII Euclidean distance: [1] SPAN, “Measured channel impulse response data set,” http://span.ece.utah.edu/pmwiki/pmwiki.php?n=Main.MeasuredCIRDataSet.

  31. dest=||estimated CIRunderattacks-chosen CIR || • dreal=||estimated CIR under attacks-real CIR|| Overall attack impact 95% 5% 0.25 0.9 is muchlargerthan withhighprobability

  32. Experimentfloorplan Helper Attacker • Place the attacker andthehelperateachpairofthe10locations:10×9=90pairs.

  33. The Euclidean distance between both estimates: Defensefeasibility evaluation Attacker: Location 2 Receiver Receiver’shelper (Location 8)

  34. Defenseperformance evaluation • Conclusion:Thehelpernodeiseffectivetohelpdetectvirtualmultipathattacks.

  35. Locationdistinction Content • Virtualmultipathattacks • Defense • Experiment • Summary

  36. Weidentifieda new attack against existing location distinction approaches that built on the spatial uncorrelation property of wireless channels. • Weproposed a detection technique that utilizes a helper receiver to identify the existence of virtual channels. Summary

  37. Thankyou!Anyquestions?

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