Transcript PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for

PReFilter: An Efficient Privacy-preserving Relay
Filtering Scheme for Delay Tolerant Networks
Rongxing Lu, Xiaodong Lin, Tom Luan,
Xiaohui Liang, Xu Li, Le Chen, and Xuemin (Sherman) Shen
University of Waterloo & UOIT & INRIA Lille
Presenter: Rongxing Lu
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Outline
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Introduction of Delay Tolerant Networks
Security & Privacy Challenges in DTNs
Proposed PReFilter Scheme
Security Analysis
Performance Evaluation
Conclusions
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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Introduction
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Infrastructure  Non-infrastructure
High density  Low density
Performance : Highly depend on mobility
Delay Tolerant Network (DTN)
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High transmission delay
Frequent link disruption
Non-exist end-to-end connections
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Applications of DTN
Inter-planetary communication
Vehicular Ad-hoc Network
Networking in sparse rural area
Underwater Sensor Network
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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DTN Routing
• DTN Routing
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increase the delivery ratio
reduce the average delay
• Single copy  Multi-copy
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• Balance Performance & Resource Consumption
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Probabilistic routing
Spray and wait
Relaycast
[1] A. Lindgren, A. Doria, and O. Schelen, “Probabilistic routing in intermittently connected networks,” Mobile Computing and
Communications Review, vol. 7, no. 3, pp. 19–20, 2003.
[2] T. Spyropoulos, K. Psounis, and C. S. Raghavendra, “Spray and wait: an efficient routing scheme for intermittently connected
mobile networks,” in Proc. of WDTN ’05, 2005, pp. 252–259.
[3] U. Lee, S. Y. Oh, K.-W. Lee, and M. Gerla, “Relaycast: Scalable multicast routing in delay tolerant networks,” in Proc. of
ICNP’08, 2008.
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Security Challenges
• Without solving security issues
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well-designed DTN routing not practical
• Selfish issues
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incentive mechanism
avoid black/grey hole
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Selfish
Selfish
Incentive
Selfish
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[1] S. Upendra, H. H. Song, L. Qiu, and Y. Zhang, “Incentive-aware routing in dtns,” in Proc. of ICNP’08, 2008, pp. 238–247.
[2] R. Lu, X. Lin, H. Zhu, X. Shen, and B. R. Preiss, “Pi: a practical incentive protocol for delay tolerant networks,” IEEE
Transactions on Wireless Communications, vol. 9, no. 4, pp. 1483–1493, 2010.
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Security Challenges (2)
• Traffic storm problem
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caused by the malicious nodes
false data  waste scarce DTN resources
• Countermeasure
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fundamental packet authentication
access control
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detect false data by relay nodes
drop false data early
save scarce DTN resources
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[1] N. Asokan, K. Kostiainen, P. G. J. Ott, and C. Luo, “Towards securing disruption-tolerant networking,” Nokia Research, Tech.
Rep. NRC-TR-2007-007.
[2] H. Zhu, X. Lin, R. Lu, X. Shen, D. Xing, and Z. Cao, “An opportunistic batch bundle authentication scheme for energy
constrained DTNs,” in Proc. IEEE INFOCOM’10, 2010, pp. 605–613.
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Security Challenges (3)
• Encrypted “junk” packet --- New Challenge
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encrypted, sent by the legitimate nodes
“junk” of no interest to the destination
decrypted, discarded by the destination
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• But, before being discarded
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TTL expire
or encounter with destination
also waste scarce DTN resources
• No countermeasure,
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encrypted
sent by legitimate nodes
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Our Contribution
• From traditional Email System  DTN
Filtering
Keyword
• Differences
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Transmission: Infrastructure  DTN nodes
Filtering: centralized  decentralized (effectively filter)
Privacy: protected  easily violated
• Our Contribution
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PReFilter: Privacy-preserving relay filtering for DTN
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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Our PReFilter Scheme
• Each node sets its filtering keyword list
• Distribute encrypted keyword list to its friends
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friends can use the encrypted keyword list for filtering
but cannot read the keywords in plaintext
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FPi
N1
Rule 1
Rule 2
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FPi
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FPi
Social Connection
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N5
N2
N7
N2
N4
N1
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FPi
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FPi
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N4
N3
Sparse DTN
N8
N6
• Packet format
Destination
Keyword
Payload
TTL
Authenticator
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PReFilter Mechanism
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Junk packet
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Source
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Destination
Intermediate node w/o packet dropping
Destination’s friend
Intermediate node with packet dropping
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Security Analysis
• Achieve
 privacy-preserving policy
distribution
 privacy-preserving filtering
 integrity, confidentiality
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Performance Evaluation
1000 m x 1000 m
Simulation Area
Random waypoint model
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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Performance Evaluation
Delivery ratio in forwarding ordinary beneficial packets with different n,
v and tr
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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Performance Evaluation
Average delay and network storage cost in forwarding ordinary
beneficial packets with different n, v and tr
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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Performance Evaluation
Average network storage cost in forwarding a “junk” packet under
PReFilter with different n, v and tr
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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Performance Evaluation
Average replicas distribution of a “junk” packet under with different n,
v and tr
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Conclusion
• In this talk, we have discussed a Privacypreserving relay filtering (PReFilter) scheme for
DTNs
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Privacy-preserving filtering policy distribution
Relay node to filter “junk” packets as early as possible
Avoid the significant waste of scarce DTN resources
• In our future work,
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Heterogeneous mobility of DTN nodes
Distribute the filtering policy at high social friend nodes
Thank you!
R. Lu et al., PReFilter: An Efficient Privacy-preserving Relay Filtering Scheme for Delay Tolerant Networks
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