De#anonymizing,Social,Networks, and,Inferring,Private,Attributes, - - PowerPoint PPT Presentation

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De#anonymizing,Social,Networks, and,Inferring,Private,Attributes, - - PowerPoint PPT Presentation

De#anonymizing,Social,Networks, and,Inferring,Private,Attributes, Using,Knowledge,Graphs, Jianwei Qian Xiang#Yang Li Illinois Tech USTC,/Illinois Tech Chunhong Zhang Linlin Chen BUPT Illinois Tech Outline Background Prior Work Our Work


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De#anonymizing,Social,Networks, and,Inferring,Private,Attributes, Using,Knowledge,Graphs,

Jianwei Qian Xiang#Yang Li

Illinois Tech USTC,/Illinois Tech

Chunhong Zhang Linlin Chen

BUPT Illinois Tech

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Outline

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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Background Prior Work Our Work Conclusion

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Background

  • Tons of social network data
  • Released to third-parties for research and business
  • Though user IDs removed, attackers with prior

knowledge can de-anonymize them. → privacy leak

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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Attacking Process

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

4 Prior k.g.

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Prior k.g.

Privacy leaked!

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Attack,Stage,1

De#Anonymization

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Which is Alice? Which is Bob?

Direct privacy leak

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Attack,Stage,2

Privacy Inference

  • Correlations between attributes/users

– Higher education => higher salary – Colleagues=> same company – Common hobbies => friends

  • Infer new info that is not published

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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Indirect privacy leak

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What,Do,We,Want,to,Do? To understand

How privacy is leaked to the attacker

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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Outline

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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Background Prior Work Our Work Conclusion

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Prior,Work

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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  • Degree attack [SIGMOD’08]
  • 1-neighborhood attack [INFOCOM’13]
  • 1*-neighborhood attack [ICDE’08]
  • Friendship attack [KDD’11]
  • Community re-identification

[SDM’11]

  • k-degree anonymity
  • 1-neighborhood anonymity
  • 1*-neighborhood anonymity
  • "#-degree anonymity
  • k-structural diversity

De-anonymize one user

Fight

Never ending! Assume specific prior knowledge!

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Prior,Work

De-anonymize all the users

– Graph mapping based de-anonymization

[WWW’07, S&P’09, CCS’12, COSN’13, CCS’14, NDSS’15]

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

11 Twitter Flickr Mapping

Attacker holds an auxiliary SN that

  • verlaps with the published SN
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Limitations

  • Assume attacker has specific prior knowledge

– We assume diverse and probabilistic knowledge

  • Focus on de-anonymization only. How attacker infers

privacy afterwards is barely discussed

– We consider it as 2nd attacking step!

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Outline

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

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Background Prior Work Our Work Conclusion

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Goals

  • To construct a comprehensive and realistic model of

the attacker’s knowledge

  • To use this model to depict how privacy is leaked.

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Challenges

  • Hard to build such an expressive model, given that

the attacker has various prior knowledge

  • Hard to simulate attacking process, since the

attacker has various techniques

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Solution

Use knowledge graph to model attacker’s knowledge

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Knowledge Graph

  • Knowledge => directed edge
  • Each edge has a confidence score

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What’s Privacy?

  • Every edge is privacy
  • Privacy is leaked when $% e − $((*) > -(*)

De-anonymizing Social Networks and Inferring Private Attributes Using Knowledge Graphs

18 Prior Posterior

Say 30%

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De#Anonymization

argmax34567(8%,8:) 4567 8%,8: = ∑ 4(5, =)

(>,?)∈7

, S is node similarity function

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Prior knowledge 8% Anonymized graph 8:

Mapping A

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Node Similarity

  • Attribute Similarity

– Use Jaccard index to compare attribute sets

  • Relation similarity

– Inbound neighborhood – outbound neighborhood – l-hop neighborhood

4B 5, = = C>4> 5,= + CE4E 5, = + CF4F 5,=

4 5, = = CG4G 5, = + 1 − CG 4B 5, =

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Problem Transformation

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8: 3I: (millions)

…… ……

Mapping => Max weighted bipartite matching I% 8%

Huge complexity!

Naïve3method:

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3I: (millions)

Top#k Strategy

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≤ "3I%

Suppose k=2

8:

3 1

I% 8%

Alice

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How,to,Choose, Top#k Candidates?

  • Intuition

– If two nodes match, their neighbors are also very likely to match.

  • Perform BFS on 8%

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Bob

2 1

Alice

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Complexity Analysis

Time Space

Building Bipartite Finding Matching

Naïve method I%I: [ I% + I: I%

#I:

[ I% + I:

#

Top-k strategy ≪ I%I: [ "#I%

]

[ "#I%

#

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Complexity3greatly reduced!

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Tradeoff

  • " balances accuracy and complexity
  • " = 10 is enough to achieve high accuracy

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0.2 0.4 0.6 0.8 1 10 20 30 40 50 60 70 80 k

sr=0.4 sr=0.6 sr=0.8

Accuracy

10 15 20 25 30 35 40 45 50 10 20 30 40 50 60 70 80 k

sr=0.4 sr=0.6 sr=0.8

Time

k k

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Privacy inference

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Predict new edges in knowledge graph

Kobe Bryant Nick Young teammate playInLeague teamInLeague

  • pponent

playFor LA Lakers playFor NY Knicks

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Path,Ranking Algorithm

  • Proposed by Ni Lao et al. in 2011 for a different topic
  • Correlations => “rules” => paths
  • Logistic regression

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Alice AIDS

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Experiments

  • Datasets

– Google+, Pokec

  • Steps

– Generate 8: – Generate 8% – Run the algorithms

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De#Anonymization Results

Metrics: accuracy, run time

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10 20 30 40 50 60 70 80 Load Build Match Total Run Time(x102s)

RS EG RW

Accuracy 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Accuracy

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.2 0.4 0.6 0.8 1 0 5 10 15 20 25 30 35 40 Accuracy Run Time(s) wA

Acc Time

0.2 0.4 0.6 0.8 1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Accuracy smin

k=5 k=10 k=15

De-anonymize about 60% of users

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Privacy Inference Results

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Metrics: hit@k, MRR (Mean reciprocal rank )

0.2 0.4 0.6 0.8 1 1.2 10 20 30 40 50 60 70 80 90 1 2 3 4 5 6 MRR(%) Hit@10(%) sr

MRR MRR,RG Hit Hit,RG

0.5 1 1.5 2 2.5 10 20 30 40 50 60 70 80 90 0 2 4 6 8 10 12 MRR(%) Hit@10(%) sr

MRR MRR,RG Hit Hit,RG

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 5 10 15 20 25 30 35 MRR(%) Hit@10(%) Sample Ratio

MRR MRR,RG Hit Hit,RG

5 10 15 20 25 30 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 25 30 35 40 45 50 55 60 65 70 75 MRR(%) Hit@10(%) Sample Ratio

MRR MRR,RG Hit Hit,RG

Infers much more privacy than random guess

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Outline

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Background Prior Work Our Work Conclusion

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Conclusion

We have

  • Applied knowledge graphs to model the attacker’s

prior knowledge

  • Studied the attack process: de-anonymization &

privacy inference

  • Designed methods to perform attack
  • Done simulations and evaluations on two real

world social networks

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Future work

  • Effective construction of the bipartite for large scale

social networks

  • Impact of adversarial knowledge on de-

anonymizability

  • Fine-grained privacy inference on the knowledge

graph

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Thank you!

Jianwei Qian jqian15@hawk.iit.edu https://sites.google.com/site/jianweiqianshomepage

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