N-party BAR Transfer

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.