# N-party BAR Transfer.

*X. Vilaça, J. Leitão, M. Correia and L. Rodrigues.*
Selected sections of this report were published in the the 15th International
Conference On Principles Of DIstributed Systems (OPODIS),
Toulouse, France, December, 2011.

## Abstract

We introduce the N-party BAR transfer problem that consists in
reliably transferring arbitrarily large data from a set of N
producers to a set of N consumers in the BAR model, i.e., in the
presence of Byzantine, Altruistic, and Rational participants. The
problem considers the existence of a trusted observer that gathers
evidence to testify that the producers and consumers have
participated in the transfer. We present an algorithm that solves
the problem for *N > 2f+1*, where *f* is the maximum
number of Byzantine processes in each of the producer and consumer
sets. We do not impose limits on the number of Rational
participants, although they can deviate from the algorithm to
improve their utility. We show that our algorithm provides a Nash
equilibrium. We argue that a N-party BAR transfer algorithm is an
important building block to support fault-tolerant distributed
computations in peer-to-peer systems.
*Also available extended report (pdf)
*

*
*

*
Luís Rodrigues
*