Secure token passing at application level

We introduce an application level implementation of a token passing operation. After an introduction that explains the conceptual principles, we describe exhaustively the state machines that implement our solution. The security requirements are carefully considered, since the token is a sensitive resource, but without introducing scalability limits. We aim at a general purpose token passing primitive: we do not enter the domain of the distributed coordination algorithms that can be implemented using the proposed operation. We discuss its practical utilization, and we indicate as primary application area the coordination of servers in a distributed infrastructure: this matches service oriented Grids as well as other emerging paradigms. Its usage is explained with a simplified use case. A working prototype exists, and we report about experimental results that confirm our claims concerning performance. (C) 2009 Elsevier B.V. All rights reserved.