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Daniele Quercia, Manish Lad, Stephen Hailes, Licia Capra, and Saleem Bhatti CS department University College London {d.quercia}@cs.ucl.ac.uk. STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions. SAC. April 2006. Daniele Quercia.
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Daniele Quercia, Manish Lad, • Stephen Hailes, Licia Capra, • and Saleem Bhatti • CS department • University College London • {d.quercia}@cs.ucl.ac.uk STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions SAC April 2006
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions Outline Mesh Net and its tragedy To avoid tragedy, STRUDEL supports 4 features Novel and existing mechanisms to support those features How STRUDEL supports them? State machine One experiment & Conclusion 2 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions Mesh net and its tragedy Mesh nodes form a peering coalition Result: Bandwidth sharing Free-riders join the coalition Result: Tragedy (of the commons) 3 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions To avoid tragedy, STRUDEL supports 4 Features STRUDEL needs distributed mechanisms to: form peering coalitions; detect free-riders; manage (trust) info; decide such that free-riders excluded. 4 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions Novel and existing work to support... form detect manage decide 5 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions form detect manage decide STRUDEL needs to form peering coalitions. How? Common(Connection sharing in MANETs): Each device in turn acts as a gateway pz px py 6 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions form detect manage decide Novel (Connection sharing in Mesh Nets): Devices share multiple connections simultaneously pz px CPD py M. Lad, S. Bhatti, S. Hailes, and P. Kirstein. Enabling Coalition-Based Community Networking. In Proc. of the London Communications Symposium. 2005. 7 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions form detect manage decide STRUDEL needs to detect free-riders. How? 2-ACKscheme: packet packet px py pz One-hop ACK Two-hop ACK Two-hop ACK If px does not receive: one-hop ACK retransmits two-hop ACK is suspicious about py 8 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions form detect manage decide STRUDEL needs to manage trust info. How? 9 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions form detect manage decide Quercia; Hailes; Capra B-trust: Bayesian Trust Framework for Pervasive Computing Proceedings of the 4th International Conference on Trust Management. LNCS. 2006. 10 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions form detect manage decide Upon trust info, STRUDEL (px) needs to decide whether to exclude (cooperate). How? For each next-hop py, px has a table: (b) py’s actions Send now Send Just-in-time Send Out-of-time (c) Expected Outcomes Sent just-in-time Sent out-of-time Sent Send (a)px’s actions Don’t send Not sent Quercia ; Hailes Risk Aware Decision Framework for Trusted Mobile Interactions Proceedings of the 1st IEEE SECOVAL Workshop (in conjunction with SECURECOMM). 11 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions Support of the 4 Features CPD 2-ACK B-trust Utility How ? 12 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions How? State Machine! WaitReady Next Hop: px selects whether to send packets and, if so, chooses its next-hop Update: px updates its direct trust and recommended trust in its next-hops 13 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions How? State Machine Send: px sends packets without 2-ACK scheme; Slow Start: px sends q packets (initially, q=1). If it receives 2-hop ACK, px increases its sending window by q. Maliciousness avoidance: px increases linearly its sending window 14 SAC
Daniele Quercia When using STRUDEL, px successfully sent . 67% of the packets on average (if n=2), . 84% (if n=4), in contrast to 42% when using random selection. STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions One experiment 100% fm m 70% px b 30% fb 15% 15 SAC
Daniele Quercia STRUDEL: Supporting Trust in the Dynamic Establishment of peering coaLitions Conclusion STRUDEL forms peering coalitions detects free-riders manages trust info, upon which it teams up only with trustworthy peers Future work: Fully implement STRUDEL 16 SAC