tailieunhanh - Lecture notes on Computer and network security: Lecture 26 - Avinash Kak

Lecture 26, small-world peer-to-peer networks and their security issues. This chapter include objectives: differences between structured P2P and small-world P2P, freenet as originally envisioned by Ian Clarke, the small-world phenomenon, demonstration of the small-world phenomenon by computer simulation, decentralized routing in small-world networks,. | Lecture 26: Small-World Peer-to-Peer Networks and Their Security Issues Lecture Notes on “Computer and Network Security” by Avi Kak (kak@) April 14, 2016 2:55pm c 2016 Avinash Kak, Purdue University Goals: 1. Differences Between Structured P2P and Small-World P2P 2. Freenet as Originally Envisioned by Ian Clarke 3. The Small-World Phenomenon 4. Demonstration of the Small-World Phenomenon by Computer Simulation 5. Decentralized Routing in Small-World Networks 6. Small-World Based Examination of the Original Freenet 7. Sandberg’s Decentralized Routing Algorithm for Freenet 8. Security Issues with the Freenet Routing Protocol 9. Gossiping in Small-World Networks CONTENTS Section Title Page Differences Between Structured P2P and Small-World P2P 3 Freenet as Originally Envisioned by Ian Clarke 6 The Small-World Phenomenon 15 Demonstration of the Small-World Phenomenon by Computer Simulation 19 Decentralized Routing in Small-World Networks 41 Small-World Based Examination of the Original Conceptualization of Freenet 48 Sandberg’s Decentralized Routing Algorithm for Freenet 50 Security Issues with the Freenet Routing Protocol 68 Gossiping in Small-World Networks 71 For Further Reading 76 Computer and Network Security by Avi Kak Lecture 26 : DIFFERENCES BETWEEN STRUCTURED P2P AND SMALL-WORLD P2P • First of all, both structured and small-world P2P networks are most commonly overlaid on top of the internet. So we can refer to them as structured P2P overlays and small-world P2P overlays. • As we saw in Lecture 25, structured P2P overlays place topological constraints on what other nodes any given node is aware of for the purpose of data lookup or data retrieval. In a structured P2P overlay, a more-or-less uniformly distributed integer, nodeID, is assigned to each node. In the Chord protocol, for example, a node is aware of its immediate successor, which would be a node with