T ransforming A utomatically B PMN Models to S mart Contracts with Nested Trade Transactions (TABS+)

Abstract

Development of blockchain smart contracts is more difficult than mainstream software development because the underlying blockchain infrastructure poses additional complexity. To ease the developer's task of writing smart contract, we use Business Process Model and Notation (BPMN) modeling to describe application requirements for trade of goods and services and then transform automatically the BPMN model into the methods of a smart contract. In our previous research we described our approach and a tool to T ransform A utomatically B PMN models into S mart contracts ( TABS ). In this paper, we describe how the TABS approach is augmented with the support for a BPMN trade transaction that is a collaboration by several actors. Our approach analyzes the BPMN model to determine which patterns in the BPMN model are suitable for use as trade transactions and show those patterns to the developer who decides which ones should be deployed as trade transactions. We describe how our approach automatically transforms the BPMN model into a smart contract that provides a transaction mechanism to enforce the transactional properties of the nested transactions. Our approach greatly reduces the developer's task as synchronization of collaborative activities is provided by our approach, so that the developer needs to code only isolated tasks with well-defined inputs and outputs. We also overview the TABS+ tool we built as a proof of concept to show that our approach is feasible, and we provide estimates on the cost of supporting the nested trade transactions.