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revision 1.40 by hemppah, Fri Jan 31 09:33:29 2003 UTC revision 1.41 by hemppah, Wed Feb 5 11:50:09 2003 UTC
# Line 1  Line 1 
1    
2    We (footonote)
3    footnote:use of the plural is customary even if research paper is authored solely
4    
5  1. Approaches  1. Approaches
6    
7  -there are five approaches when performing searches in p2p networks.  -there are five approaches when performing searches in p2p networks.
# Line 36  information about O(log n) nodes Line 40  information about O(log n) nodes
40  -Of couse, there is the possibility to route in constant times, but it requires that *each** node  -Of couse, there is the possibility to route in constant times, but it requires that *each** node
41  maintains information about all the nodes in the network. Therefore , practically, this method  maintains information about all the nodes in the network. Therefore , practically, this method
42  impossible  impossible
43  -Example systems: Chord, CAN, Kademlia, Pastry, Tapestry, Viceroy  -Example systems: Chord, CAN, Kademlia, Pastry, Tapestry, Viceroy, Symphony, SkipNet, Skip Graph
44    -Example applications: CFS, PAST, Oceanstore
45    
46  *Update*  *Update*
47  -Viceroy system achieves O(log n) hops with only O(1) neighbors  -Viceroy system achieves O(log n) hops with only O(1) neighbors
# Line 1063  fault tolerant to linear number of adver Line 1068  fault tolerant to linear number of adver
1068    
1069  5.6. Attack models/behavior of faulty nodes  5.6. Attack models/behavior of faulty nodes
1070    
1071  1) Sybil attack \cite{douceur02sybil}  1) Sybil attack \cite{douceur02sybil}
1072  2) Fail-stop  2) Fail-stop
1073  3) Spam generating model \cite{naor03simpledht}  3) Spam generating model \cite{naor03simpledht}
1074  4) Byzantine problem \cite{357176}, p2p domain \cite{296824}  4) Byzantine problem \cite{357176}, p2p domain \cite{296824}
1075    
1076    Solutions for Sybil Attack:
1077    1) data replication among several peers
1078    2) data fragmentation among several peer
1079    
1080    BUT:
1081    -in either case, both approaches assumes that two different remote entities are actually different; sybil attacks are still possible --> need for centralized authority
1082    -in p2p environment, trusting to collective assurance of multiple signatories (like PGP) is not safe/undermines the authenticity of system (because of sybil attacks)
1083    -\cite{douceur02sybil} argues that Sybil attacks are always possible except under extreme and unrealistic assumptions of resource parity and coordination among entities
1084    
1085    Current research with regard to p2p security:
1086    -lot of done has been done on persistence
1087    -little has been done on distinctness (sybil attack)
1088    -computational puzzles for preventing DDOS attacks (force attacker perform more work than victim)
1089    -puzzles can be used for accountability (Dingeline, in Peer-to-Peer: Harnessing...), but can dangerous
1090    -some research has been done on on-line identities for humans. However, they often has a direct relation to phychical world
1091    
1092    
1093    
1094  6. Proposed frameworks  6. Proposed frameworks

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