a location-privacy platform for smartphone apps · a location-privacy platform for smartphone apps...
TRANSCRIPT
![Page 1: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/1.jpg)
A Location-Privacy Platform for Smartphone Apps
Saikat Guha, Mudit Jain, Venkat Padmanabhan
(Microsoft Research India)
![Page 2: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/2.jpg)
Location-Privacy Problem
• “[TaintDroid OSDI’10] studied 30 popular Android applications that use location, camera, microphone data. [They] found that 15 send users' location information to remote advertisement or analytics servers.”
![Page 3: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/3.jpg)
+37.4179, -121.9094
![Page 4: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/4.jpg)
Location-Privacy Problem
• “[TaintDroid OSDI’10] studied 30 popular Android applications that use location, camera, microphone data. [They] found that 15 send users' location information to remote advertisement or analytics servers.”
![Page 5: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/5.jpg)
Privacy-Problem on Mobiles
• App developers are given raw low-level data
– Need 3rd-party libraries to synthesize useful representations
– 3rd party libraries need to contact cloud
• Once app gets lat-long, OS cannot control what app does with it.
![Page 6: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/6.jpg)
Today: Big Picture
App
OS
GPS
Location
Location
Intent 3rd-party
Cloud Service
Phone
![Page 7: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/7.jpg)
Koi: Big Picture
App
OS
GPS
Intent
Location
Koi Privacy-Preserving
Cloud Service
Phone
![Page 8: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/8.jpg)
Koi: Raise Level of Abstraction
• For the app developer:
– Triggers and callback based API
– Rich specification of triggers, e.g.,
• “Within 5 blocks from Bob’s current location”
• “At any grocery store”
• Platform support:
– Privacy-preserving cloud service to support this abstraction.
![Page 9: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/9.jpg)
Defining Privacy
• K-anonymity, L-diversity, Differential Privacy
– Applicable to learning
– Not applicable to fine-grained personalization
• Unlinkability – “Saikat is looking for Bail-bonds” (private)
– “Someone is looking for Bail-bonds” (not-private)
– “Saikat is looking for something” (not-private)
![Page 10: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/10.jpg)
Location-Based Advertising
ZigZag Bail-Bond N 2nd St.
Saikat Bail-Bond? 5 blocks from
“current location”?
I = CreateItem(“ZigZag”) I.AddAttr(“Bail-Bond”) I.AddLocAttr(“N 2nd St., San Jose, CA”)
T = CreateTrigger(callback) T.AddAttr(“Bail-Bond”) T.AddLocAttr(“cur loc + 5blk”, True)
![Page 11: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/11.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
![Page 12: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/12.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag Bail-Bond
![Page 13: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/13.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag Bail-Bond [•]M
![Page 14: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/14.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag Bail-Bond [•]M [[•]M]C
![Page 15: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/15.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag [[•]M]C
![Page 16: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/16.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
[[•]M]C
ZigZag U1
U1
![Page 17: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/17.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
[[•]M]C
ZigZag U1
U1
![Page 18: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/18.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
[[•]M]C
ZigZag U1 U1 R1
R1
![Page 19: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/19.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
R1 [•]M
![Page 20: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/20.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
R1 [•]M
![Page 21: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/21.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
R1 Bail-Bond
![Page 22: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/22.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
![Page 23: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/23.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
![Page 24: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/24.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
![Page 25: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/25.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
Saikat “cur loc”
+ 5blk
![Page 26: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/26.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
Saikat 37.41,-121.9
+ 5blk
![Page 27: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/27.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
Saikat [[•]M]C
![Page 28: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/28.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
U2 R4
[•]M R4
![Page 29: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/29.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
U2 R4
37.41,-121.9 + 5blk
R4
![Page 30: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/30.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5blk
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
Saikat U2
R3
U2 R4
R4
![Page 31: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/31.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
Saikat
![Page 32: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/32.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
U2
![Page 33: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/33.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
R3
![Page 34: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/34.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
R1
![Page 35: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/35.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
![Page 36: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/36.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
R4
![Page 37: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/37.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
R2
![Page 38: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/38.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
![Page 39: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/39.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
U2 U1
![Page 40: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/40.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
ZigZag Saikat
![Page 41: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/41.jpg)
Koi: Privacy-Preserving Matching
ZigZag Bail-Bond
N 2nd St. Saikat Bail-Bond
“cur loc” + 5
Matcher Combiner
ZigZag U1 U1 R1
Bail-Bond
R1
U1 R2
N 2nd St. R2
U2 R3
U2 R4
Saikat U2
R3
R4
Saikat
ZigZag
![Page 42: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/42.jpg)
Koi Features
• Matching based on attribute plain-text
– Location, spelling correction, translation
– Other semantic transformation
• OS can auto-update location attributes
– Without waking app up
![Page 43: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/43.jpg)
Koi Applications: Location-Based …
• Advertising
• Content tagging (photos, etc.)
• Search
• Recommendations
• Social networking
• Navigation
![Page 44: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/44.jpg)
Koi: Private Mobile Social Network
Rob ES (me:saikat)? cur loc + 5blk?
Saikat ES(me:saikat) cur loc ER (fr:rob)
Bob ER (fr:rob)? cur loc + 5blk?
![Page 45: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/45.jpg)
Koi: Private Navigation
Saikat cur loc to ZigZag?
37.41,-121.9 to ZigZag?
D0 Turn left
D1 Turn right
D2 Turn around
Turn left? 37.42,-121.8
to ZigZag? Turn right?
![Page 46: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/46.jpg)
Privacy-Properties
• Proverif Automated Theorem Prover
• Model Koi protocol in applied pi-calculus – Unlinkability (using Proverif secrecy)
– Adversary (spy channels; Honest-but-Curious)
– Datastore (using Proverif asynchronous channels)
• Proofs for: 1. User cannot be linked with attribute
2. User’s multiple attributes cannot be linked
3. Matched users cannot be linked (extn.)
![Page 47: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/47.jpg)
Malicious Applications
• Filter triggers
– By location, time-of-day, etc.
• Rate-limit triggers and callbacks
– Per user, across all users, etc.
• Sybil apps trying to stay under threshold
– Economic burden (developer key costs $$)
![Page 48: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/48.jpg)
Implementation and Deployment
• Koi Matcher service implemented and publicly deployed
– REST based API
– HTML5 (mobile) browsers, and C# bindings
– Scales well
• Combiner:
– “Bring-your-own-combiner”
– Or use our combiner (uhhh…)
![Page 49: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/49.jpg)
Summary
• Current Get-Lat-Long API is bad for privacy
• Koi raises the level of abstraction
– Simple yet powerful abstraction
– Easy for app-developers to use
– Allows platform to provide user privacy
• Proverif is a cool tool
![Page 50: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/50.jpg)
Adoption Incentives
• Up to the platform
• Positive feedback:
– Higher placement on app marketplace for apps not using legacy location API
• Negative feedback:
– More nag screens for apps using legacy API
• Enforcement:
– Block legacy API for free apps
![Page 51: A Location-Privacy Platform for Smartphone Apps · A Location-Privacy Platform for Smartphone Apps Saikat Guha, Mudit Jain, Venkat Padmanabhan (Microsoft Research India)](https://reader033.vdocuments.mx/reader033/viewer/2022043014/5faffee20db4eb383e312b9e/html5/thumbnails/51.jpg)
Collusion
• Combiner
– Allow privacy-advocates (EFF, ACLU), anti-virus companies, certificate agencies (Verisign), non-profits (Mozilla), to run combiner.
– Their existence entirely dependent on public trust
• Matcher
– User picks combiner (out of hundreds). Matcher needs to collude with many to be effective. Quickly discovered.