UsablePIR NDSS'08,SanDiego,CA PeterWilliams - - PowerPoint PPT Presentation

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UsablePIR NDSS'08,SanDiego,CA PeterWilliams - - PowerPoint PPT Presentation

Mar 08, 2024 204 likes •442 views

NetworkSecurityandApplied CryptographyLaboratory http://crypto.cs.stonybrook.edu UsablePIR NDSS'08,SanDiego,CA PeterWilliams petertw@cs.stonybrook.edu RaduSion sion@cs.stonybrook.edu

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SLIDE 1
  • UsablePIR

NDSS'08,SanDiego,CA

NetworkSecurityandApplied CryptographyLaboratory

PeterWilliams petertw@cs.stonybrook.edu RaduSion sion@cs.stonybrook.edu http://crypto.cs.stonybrook.edu

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SLIDE 2

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Overview:PIR
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SLIDE 3

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • TypesofPIR
  • !"#$ "%
  • %&'("%

) *+,(+ ) --.',+"% ) -(+

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SLIDE 4

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

/

Past:cPIRisimpractical

Sion&Carbunar@NDSS2007

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SLIDE 5

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

Future:cPIRisimpractical

Sion&Carbunar@NDSS2007

(logarithmic)

Thewizardpredicts-

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SLIDE 6

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • “ObliviousRAM”

RAM CPU

Access Pattern Privacy Protocol Write Read Outsourced Data EncryptedDataBlock DataBlock

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SLIDE 7

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

1

CanweuseORAM? Remote Un3trusted Server

Data ORAM

Trusted Party

ClientA ClientC ClientB PIR

MainIdea:ORAM+TrustedParty=PIR

Asonov,Smithandothers Makethispractical!

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SLIDE 8

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • ORAMOverview

Level0:1bucket Level1:4buckets Level2:16buckets Level:/ buckets Query

ORAM:Ostrovsky,1996

Fake“bucketfiller” DataItem

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SLIDE 9

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

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ORAM:Levelfull?

Fake“bucketfiller” DataItem

ORAM:Ostrovsky,1996

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SLIDE 10

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • ORAM:Howtore3shuffle?

b

sorting network ORAM:Ostrovsky,1996

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SLIDE 11

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Re3shuffle:faster?
  • un>trusted

server ORAM client

x

  • 1

2

  • 3

x

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SLIDE 12

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Removefakes

) (&3+( ) 4+5

Smalllocalbuffer (read/writeprivacy) Download Bucket Discard Fakes Largeremotebuffer (noprivacy) UntrustedServer Client Encryptitems

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SLIDE 13

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Re3shuffle:mergesort
  • un>trusted

server ORAM client

x

  • 1

2

  • 3

x

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SLIDE 14

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

/

Mergesortonrandomkeys input:items, nomorefakes

  • utput:sorted
  • ncryptohash
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SLIDE 15

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

Sort

) %54+&&,'+ ) 6#5.+'(7(3#'

Arraystosort remote> noreadprivacy smallbuffer local> readprivacy Output: real>timebuffersizes

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SLIDE 16

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Re3shuffle:addnewfakes
  • un>trusted

server ORAM client

x

  • 1

2

  • 3

x

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SLIDE 17

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

1

Addnewfakes

Smalllocalbuffer (read/writeprivacy) AddFakes&Re>encrypt Largeremotebuffer, sortedbybucket (noprivacy) UntrustedServer Client Divideinto buckets

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SLIDE 18

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Costs

) 8 (& ) 9 +&&(#/ (( ) +&&& ( ) '8(,:+#&+&&5 ) ;(,:+#5 < +(38=

( )

( ) ( )

( ) ( )

( )

  • /

/ /

∑ ∑

( )

( )

  • (

)

  • /

/

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SLIDE 19

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

2

Existingwork

>( ) ?(;3#;*22 ) -'%/ ) @A-;%.- ) ,(

( )

  • /
  • (

)

  • (

)

  • (

)

  • (

)

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SLIDE 20

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Howfastcanwerun?
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SLIDE 21

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Closingin<

Conclusions

PracticalPrivateInformationRetrievalProtocol Severalqueriespersecondoverlargedatasets Fullcomputationalprivacy

FutureWork

De>amortizere>shufflecosts Reduceserverstorageoverhead> eliminateuseoffakes Newmechanismwithoverhead

( )

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SLIDE 22

UsablePrivateInformationRetrieval(NDSS2008)

StonyBrookNetworkSecurityandAppliedCryptographyLab

  • Closingin<

Thankyou!