Modelling and Executing Time-Aware Processes in Trustless Blockchain Environment

Blockchain is an emergent technology which enables the execution of collaborative business processes while ensuring trust by replacing central authority with cryptographic proof and distributed consensus. Thus, Blockchain technology can be used to find agreement between untrusted collaborating parties in business processes. However, temporal constraints of processes need more investigation. Indeed, Blockchain platforms do not offer means to represent nor to manage temporal constraints for business processes. Moreover, transaction completion time is not fixed, it can take from a few seconds to several minutes. In this paper, we include temporal constraints in smart contracts, which could mitigate the violation of time constraints, minimize the costly execution time, and avoiding thus financial penalties. To achieve this, we extend Caterpillar tool, which is the first open-source blockchain-based BPMN execution engine, to enable the automatic transformation of a large set of temporal constraints for business process model to smart contract code. We illustrate our approach with a use case, which we deploy in Ethereum Testnet.