Making Trust Explicit in Distributed Commerce Transactions

In a distributed environment where nodes are independently motivated, many transactions or commercial exchanges may be stymied due to a lack of trust between the participants. The addition of trusted intermediaries may facilitate some exchanges, but others are still problematic. We introduce a language for specifying these commercial exchange problems, and sequencing graphs, a formalism for determining whether a given exchange may occur. We also present an algorithm for generating a feasible execution sequence of pairwise exchanges between parties (when it exists). Indemnities may be offered to facilitate previously infeasible transactions. We show when and how they enable commercial transactions.