Abstract The usage of process choreographies and decentralized Business Process Management Systems has been named as an alternative to centralized business process orchestration. In choreographies, control over a process instance is shared between independent parties, and no party has full control or knowledge during process runtime. Nevertheless, it is necessary to monitor and verify process instances during runtime for purposes of documentation, accounting, or compensation. To achieve business process runtime verification, this work explores the suitability of the Bitcoin blockchain to create a novel solution for choreographies. The resulting approach is realized in a fully-functional software prototype. This software solution is evaluated in a qualitative comparison. Findings show that our blockchain-based approach enables a seamless execution monitoring and verification of choreographies, while at the same time preserving anonymity and independence of the process participants. Furthermore, the prototype is evaluated in a performance analysis.
Business process monitoring in the area of service oriented computing is typically performed using business activity monitoring technology in an intra-organizational setting. Due to outsourcing and the increasing need for companies to work together to meet their joint customer demands, there is a need for monitoring of business processes across organizational boundaries. Thereby, partners in a choreography have to exchange monitoring data, in order to enable process tracking and evaluation of process metrics. In this paper, we describe an event-based monitoring approach based on BPEL4Chor service choreography descriptions. We show how to define monitoring agreements specifying events each partner in the choreography has to provide. We distinguish between resource events and complex events for calculation of process metrics using complex event processing technology. We present our implementation and evaluate the concepts based on a scenario. Software-as-a-service (SaaS) providers are further expanding their offering by growing into the space of business process outsourcing (BPO). Therefore, the SaaS provider wants to administer and manage the business process steps according to a service level agreement. Outsourcing of business processes results in decentralized business workflows. However, current business process modeling languages, e.g. Business Process Execution Language (BPEL), Business Process Model and Notation (BPMN), are based highly on a centralized execution model and current BPMN engines offer limited constructs for federation and decentralized execution. To guarantee execution of business processes according to a service level agreement, different parties involved in a federated workflow must be able to inspect the state of external workflows. This requires advanced inspection interfaces and monitoring facilities. Current business process modeling languages must thus be extended to support monitoring in the s pecification, support modeling and support deployment of decentralized workflows. In this paper, correlation and monitoring extensions for BPMN are described. These extensions to BPMN are described such that the existing specification can still be used as is in a backwards compatible way.