Sorcery: Could We Make P2P Content Sharing Systems Robust to Deceivers? Ennan Zhai, Ruichuan Chen, Zhuhua Cai, Long Zhang, Eng Keong Lua*, Huiping Sun, Sihan Qing, Liyong Tang, and Zhong Chen (Email:
[email protected])
Peking University & *Carnegie Mellon University
Background
I
What is the deceptive behavior in P2P content sharing systems ?
II
What are the existing solutions on this problem ?
III
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Our approach ?
Ennan Zhai
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Background
I
What is the deceptive behavior in P2P content sharing systems ?
II
What are the existing solutions on this problem ?
III
IEEE P2P 2009
Our approach ?
Ennan Zhai
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Deceptive Behavior
Individual or collusive attackers (deceivers) publish some polluted content items, and cast incorrect votes on them … …
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Deceptive Behavior
Individual or collusive attackers (deceivers) publish some polluted content items, and cast incorrect votes on them … …
Normal users are deceived by votes and download these polluted content items.
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Deceptive Behavior Alice’s Content items
1
3
I would like to download File 4.
4
Alice’s Votes 1
4
Bob 7
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Deceptive Behavior
4
However, after downloading content 4, Bob finds this content item is polluted. We say Bob is deceived by Alice’s vote.
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Bob
3
Background
I
What is the deceptive behavior in P2P content sharing systems ?
II
What are the existing solutions on this problem ?
III
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Our approach ?
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Existing Solutions • Reputation Models: 9 Peer-based: EigenTrust, PeerTrust, Scrubber … 9 Object-based: Credence, FileTrust … 9 Hybrid: XRep, X2Rep, Extended Scrubber…
• Micropayment Techniques: MojoNation. • Exchange Protocol …………
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Existing Solutions • Reputation Models: 9 Peer-based: EigenTrust, PeerTrust, Scrubber … 9 Object-based: Credence, FileTrust … 9 Hybrid: XRep, X2Rep, Extended Scrubber…
• Micropayment Techniques: MojoNation. • Exchange Protocol …………
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Some Problems! Ennan Zhai
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Analysis
The above situation can be explained the attackers sit on the dominant position, and the solution is we need to achieve the conversion of the dominant position through constructing our own dominant information.
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Analysis The fundamental insight driving our work is social network can help the users construct the confidential and reliable friend-relationships, and we treat the confidential information of friends as the dominant information.
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Background
I
What is the deceptive behavior in P2P content sharing systems ?
II
What are the existing solutions on this problem ?
III
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Our approach ?
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Sorcery 1
Introducing Social Network
2
Challenge-response Mechanism
3
Punishment Mechanism
4
Practical Issues
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Sorcery 1
Introducing Social Network
2
Challenge-response Mechanism
3
Punishment Mechanism
4
Practical Issues
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Introducing Social Network
Sorcery client stores friends’ information in his friend list. This friend list is confidential to other users in the system … …
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Introducing Social Network
Sorcery client stores friends’ information in his friend list. This friend list is confidential to other users in the system … …
This is the dominant information for the client
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Introducing Social Network Eve
Alice
2
8
1
1
2
1
4
8
14
7
9
Bob
6 6
1
2
3
2
3
5
11 20
Eve is Alice’s friend, but Bob cannot know the friend-relationship between Alice and Eve. IEEE P2P 2009
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Introducing Social Network Because friends’ experiences can be used, social network can address cold start problem which cannot be solved by the existing reputation models … …
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Introducing Social Network Because friends’ experiences can be used, social network can address cold start problem which cannot be solved by the existing reputation models … …
New user joins in the system, he is easily to be deceived due to lack of experiences.
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Sorcery 1
Introducing Social Network
2
Challenge-response Mechanism
3
Punishment Mechanism
4
Practical Issues
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Challenge-response File 3 ?
Alice’s Friend list Friend1 5
1 2 3 4
Friend2
8
Bob
5
2 3 5 Alice
Friend3 1
2
Friend4
Eve 2 3 5 7
4 8
1 2 4 5 8
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Challenge-response ChallengeMessage
Alice’s Friend list Friend1 5
Step 1
(File5,?),(File3,?),(File2,?)
1 2 3 4
Friend2
8
Bob
5
2 3 5 Alice
Friend3 1
2
Friend4 4 8
Eve
Step 1
2 3 5 7 ChallengeMessage (File3,?),(File8,?),(File4,?)
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1 2 4 5 8
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Challenge-response ChallengeMessage
Alice’s Friend list Friend1 5
Step 2 (File5,-1),(File3,+1),(File2,+1)
1 2 3 4
Friend2
8
Bob
5
2 3 5 Alice
Friend3 1
2
Friend4 4 8
Eve 2 3 5 7
Step 2 ChallengeMessage (File3,-1),(File8,-1),(File4,-1)
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1 2 4 5 8
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Sorcery 1
Introducing Social Network
2
Challenge-response Mechanism
3
Punishment Mechanism
4
Practical Issues
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Punishment Mechanism
Sorcery introduces reliability degree to punish deceivers, thus reducing the possibility of impact brought by them … …
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Punishment Mechanism max(-1, RDi(j) - pn2) RDi(j)= min(1, RDi(j) + r) RDi(j): the reliability of i with respect to j; p: the penalty factor; r: the recompense factor; n: the number of i being deceived by j. IEEE P2P 2009
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Punishment Mechanism max(-1, RDi(j) - pn2) RDi(j)= min(1, RDi(j) + r)
If j is a deceiver … …
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Punishment Mechanism max(-1, RDi(j) - pn2) RDi(j)= min(1, RDi(j) + r) If j is not a deceiver, and i would like to upgrade RDi(j) … …
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Sorcery 1
Introducing Social Network
2
Challenge-response Mechanism
3
Punishment Mechanism
4
Practical Issues
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Practical Issues
• Lack of the Overlapping Votes • Unreliable Friends
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Practical Issues
• Lack of the Overlapping Votes • Unreliable Friends
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Non-overlapping Voting Histories
The studies in [J. Liang, INFOCOM’05] and [K. Walsh, NSDI’06] indicated it’s a high probability that most peers have overlapping votes with the voters of any content item … …
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Non-overlapping Voting Histories
The studies in [J. Liang, INFOCOM’05] and [K. Walsh, NSDI’06] indicated it’s a high probability that most peers have overlapping votes with the voters of any content item … … The client should challenge some of voters of the target content item (Details see paper please).
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Practical Issues
• Lack of the Overlapping Votes • Unreliable Friends
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Unreliable Friends
In the practical applications, some friends may be online deceivers or compromised, Sorcery utilizes similarity based on cosine technique to filter those unreliable friends (The concrete equation see paper please) … …
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Evaluation
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Simulation Setup
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Experimental Results
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Evaluation
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Simulation Setup
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Experimental Results
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Simulation Setup • Network Model: Gnutella Prototype • Peer Model: 5, 000 Peers • Social Model: Kleinberg Model • Content Model: ¾ 1,000 (Titles) X 500 (Versions) (50 good) ¾ Zipf Distribution a=0.8
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Evaluation
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Simulation Setup
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Experimental Results
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Normal Deceivers
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Normal Deceivers
Rate of Deceivers
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Normal Deceivers
Rate of Deceivers
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Normal Deceivers
Rate of Deceivers
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Tricky Deceivers
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Tricky Deceivers Rate that Tricky Deceivers Vote Correctly
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Tricky Deceivers Rate that Tricky Deceivers Vote Correctly
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Conclusion and Discussion
• How to resist three types of attacks? ¾ Man-in-the-Middle (MITM) Attack ¾ Sybil Attack ¾ Denial-of-Service (DoS) Attack
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Q&A
Thank you !
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