[Nets-seminars] Seminar (INFOCOM rehersal) Thursday 2nd April 4pm GS302

[Richard G. Clegg]

This Thursday (note change of day) is the last in this term's seminar 
series.

Raul Landa will speak on "A Sybilproof Indirect Reciprocity Mechanism 
for Peer-to-Peer Networks".  This is a rehersal for his Infocom 
presentation so come along with intelligent questions and suggestions 
about the presentation.

Abstract:  Although direct reciprocity (Tit-for-Tat) contribution
systems have been successful in reducing freeloading in peerto-
peer overlays, it has been shown that, unless the contribution
network is dense, they tend to be slow (or may even fail) to
converge. On the other hand, current indirect reciprocity
mechanisms based on reputation systems tend to be susceptible
to sybil attacks, peer slander and whitewashing.
In this paper we present PledgeRoute, an accounting mechanism
for peer contributions that is based on social capital.
This mechanism allows peers to contribute resources to one
set of peers and use this contribution to obtain services from
a different set of peers, at a different time. PledgeRoute is
completely decentralised, can be implemented in both structured
and unstructured peer-to-peer systems, and it is resistant to the
three kinds of attacks mentioned above.
To achieve this, we model contribution transitivity as a routing
problem in the contribution network of the peer-to-peer overlay,
and we present arguments for the routing behaviour and the
sybilproofness of our contribution transfer procedures on this
basis. Additionally, we present mechanisms for the seeding
of the contribution network, and a combination of incentive
mechanisms and reciprocation policies that motivate peers to
adhere to the protocol and maximise their service contributions
to the overlay.
-- 
Richard G. Clegg,
Dept of Elec. Eng.,
University College London
http://www.richardclegg.org/