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

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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

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 1 ETH Zurich – Distributed Computing Group

Raphael Eidenbenz, Thomas Locher, Roger Wattenhofer

Hidden Communication in P2P Networks

Steganographic Handshake and Broadcast

INFOCOM 2011

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 2

Spy Rendezvous

In London, April’s a spring month. ..whereas in St.Petersburg we’re freezing our butts off.

MI6 CIA

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 3

Spy Rendezvous

In London, April’s a spring month. Yes, Russian winters are cold. Enjoy your stay, sir.

?? CIA

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 4

Steganographic Handshake in Networks

Share files

Regular peers Conspirers

Talk to other conspirers without raising suspicion

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 5

Steganographic Handshake in Networks

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 6

?

Steganographic Handshake in Networks

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 7

?

Steganographic Handshake in Networks

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 8

Steganographic Channels

P2P File sharing

– Block request sequence – Block subset selection

Timing
Bandwidth
Ports

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 9

Steganographic Broadcast

Send a message to all conspirers
Bittorrent-like p2p file sharing system

n

c n-c

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 10

Steganographic Broadcast

Send a message to all conspirers
Bittorrent-like p2p file sharing system

k

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

Efficient Broadcast

Lemma

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 12

Efficient Broadcast

Lemma Algorithm

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

Stronger Authority Models

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 14

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

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

Reprise

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Thank You!

Questions & Comments?

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 17

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

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 18

Encoding Bits Into a Permutation

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 19

Proof of Lemma 3.2

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 20

Broadcast under Individual Monitoring

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Broadcast under Complete Monitoring

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 22

Broadcast under Stochastic Monitoring

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 23

Broadcast under Stochastic Monitoring

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ETH Zurich – Distributed Computing Group Raphael Eidenbenz, INFOCOM 2011 24

Spy Rendezvous

In London, April’s a spring month. ..whereas in St.Petersburg we’re freezing our butts off.