Hidden Communication in P2P Networks Steganographic Handshake and - PowerPoint PPT Presentation

Hidden Communication in P2P Networks Steganographic Handshake and Broadcast Raphael Eidenbenz, Thomas Locher, Roger Wattenhofer INFOCOM 2011 ETH Zurich – Distributed Computing Group ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 1

Spy Rendezvous In London, April’s a spring month . ..whereas in St.Petersburg we’re freezing our butts off. CIA MI6 ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 2

Spy Rendezvous In London, April’s a spring month . Yes, Russian winters are cold. Enjoy your stay, sir. CIA ?? ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 3

Steganographic Handshake in Networks Regular peers Conspirers Share files Talk to other conspirers without raising suspicion ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 4

Steganographic Handshake in Networks ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 5

Steganographic Handshake in Networks ? ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 6

Steganographic Handshake in Networks ? ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 7

Steganographic Channels • P2P File sharing – Block request sequence – Block subset selection • Timing • Bandwidth • Ports ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 8

Steganographic Broadcast • Send a message to all conspirers n • Bittorrent-like p2p file sharing system c n-c ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 9

Steganographic Broadcast • Send a message to all conspirers • Bittorrent-like p2p file sharing system k ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 10

Efficient Broadcast Lemma ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 11

Efficient Broadcast Lemma Algorithm ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 12

Stronger Authority Models ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 13

Steganographic Handshake in BitThief • BitThief is a BitTorrent client that – Free rides with BitTorrent clients [1], and – Trades tit-for-tat (T4T) with other BitThiefs [2] • Block request sequence • Hybrid approach using PEX – Order of peer addresses – Forged peer address [1] Locher et al., Free Riding in Bittorrent is Cheap , HotNets 2006 [2] Locher et al., Rescuing Tit-for-Tat with Source Coding , P2P 2007 ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 14

Reprise ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 15

Thank You! Questions & Comments?

References • P. Erdös and A. Rényi, On Random Graphs , Publicationes Mathematicae, 1959. • R. Van der Hofstad, Random Graphs and Complex Networks , 2007. • BitThief – A Free Riding BitTorrent Client . http://bitthief.ethz.ch • Locher et al., Free Riding in Bittorrent is Cheap , HotNets 2006 • Locher et al., Rescuing Tit-for-Tat with Source Coding , P2P 2007 ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 17

Encoding Bits Into a Permutation ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 18

Proof of Lemma 3.2 ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 19

Broadcast under Individual Monitoring ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 20

Broadcast under Complete Monitoring ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 21

Broadcast under Stochastic Monitoring ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 22

Broadcast under Stochastic Monitoring ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 23

Spy Rendezvous In London, April’s a spring month . ..whereas in St.Petersburg we’re freezing our butts off. CIA MI6 ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 24