Evaluation of the iterative multiplication strategy for trust propagation in pervasive environments

There are a number of models for access control in pervasive environments that are based on trust propagation. Iterative multiplication of the trust values on a path from a source entity to a target entity is one of the common strategies for trust propagation. In this paper, we evaluate the effectiveness of iterative multiplication for trust propagation. The data set used for this evaluation is the real web of trust of Advogato.org that comprises of over 11,000 vertices (users) and over 50,000 directed weighted edges (trust relationships between users). We find that a significantly strong positive linear correlation exists between trust values based on direct experience and the corresponding propagated trust values derived through the iterative multiplication approach. This finding provides empirical support for the access control models for pervasive environments that employ the iterative multiplication strategy for trust propagation.