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Is Internet communication

private?

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Types of AttacksTypes of Attacks

Active AttacksActive Attacks

Passive AttacksPassive Attacks

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Active Attack

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Passive Attack

EavesdroppingEavesdropping

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Eavesdropping is the act of secretly listening to the private conversation of others without their consent.

What is going on

inside?????

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Onion RoutingOnion Routing SSenderender and the and the receiverreceiver nodes nodes

communicatecommunicate with each other with each other anonymouslyanonymously by means of some by means of some intermediate nodesintermediate nodes called as called as onion routersonion routers..

Network Network InfrastructureInfrastructure

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Proxy Proxy InterfacesInterfaces

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Defining a routeDefining a routeConstructing an anonymous connection Constructing an anonymous connection and onionand onionMoving onion through an anonymous Moving onion through an anonymous connectionconnectionDestroying the anonymous connectionDestroying the anonymous connection

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E4pu (3’s IP address, E3pu ((5’s IP E4pu (3’s IP address, E3pu ((5’s IP address, (E5pu (recipient’s IP address, (E5pu (recipient’s IP address, data)))))address, data)))))

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The size of the onion reduces as it The size of the onion reduces as it nears the destinationnears the destination Every onion router has details of only Every onion router has details of only its previous and next hopits previous and next hopAn attacker might compromise a An attacker might compromise a router, acquires private key and router, acquires private key and decrypts data.decrypts data. Packet delivery is not ensuredPacket delivery is not ensured

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Anonymous Chatting

Web Browsing

Anonymous Cash

Remote Login

Electronic Mail

•The purpose of onion Routing is to protect the anonymity of a user who wants to communicate over a network.

•Resistant to Eavesdropping.

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Referenceshttp://www.ietf.org/rfc/rfc793.txtM. Reed, P. Syverson, D. Goldschlag,

"Anonymous Connections and Onion Routing", IEEE Symposium on Security and Privacy (1997)

http://tor.eff.org/tor-design.pdfhttp://tor.eff.org/

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