Pupa: Smart Contracts for BPMN with Time-Dependent Events and Inclusive Gateways

Abstract

AbstractThe digital transformation of business processes faces a major hindrance due to the lack of trust and transparency. As blockchain and other distributed ledger (DLT) are considered key enabling technologies, there is a need for supporting tools which can deploy business models over smart contracts in order to leverage these decentralized platforms. Existing blockchain-based Business Process Management (BPM) solutions support various blockchain platforms and different types of modelling language, i.e., Ethereum and Business Process Model Notation (BPMN). However, the majority of these methods do not support processes with time events and inclusive gateways due to severe limitations imposed by smart contract programming languages. In other words, mainstream blockchain platforms do not offer a straightforward way to execute a transaction at a later time. To overcome these aforementioned issues, we propose an engine called Pupa, a blockchain-based decentralized protocol to translate business processes with time events and inclusive gateways to smart contracts. Pupa accomplishes this by adding task feature to time events, check function on top of activities succeeding time events and, listening variables to sequence flow forking or joining inclusive gateways. We implemented Pupa by extending Caterpillar, an existing BPMN solution using Solidity and Ethereum, and evaluated the performance of our proposed engine and its generated smart contracts with a baseline solution. Our results show that Pupa is competitive with baseline solutions in terms of cost and performance, while offering additional advantages in terms of decentralization and supporting additional BPMN semantics.KeywordsBlockchainBusiness process managementSmart contractBPMNTimerInclusive gateway