Interpreted Execution of Business Process Models on Blockchain

Abstract

Blockchain technology provides a tamper-proof mechanism to execute inter-organizational business processes involving mutually untrusted parties. Existing approaches to blockchain-based process execution are based on code generation. In these approaches, a process model is compiled into one or more smart contracts, which are then deployed on a blockchain platform. Given the immutability of the deployed smart contracts, these compiled approaches ensure that all process instances conform to the process model. However, this advantage comes at the price of inflexibility. Any changes to the process model require the redeployment of the smart contracts (a costly operation). In addition, changes cannot be applied to running process instances. To address this lack of flexibility, this paper presents an interpreter of BPMN process models based on dynamic data structures. The proposed interpreter is embedded in a business process execution system with a modular multi-layered architecture, supporting the creation, execution, monitoring and dynamic update of process instances. For efficiency purposes, the interpreter relies on compact bitmap-based encodings of process models. An experimental evaluation shows that the proposed interpreted approach achieves comparable or lower costs relative to existing compiled approaches.Index Terms-Blockchain, Model-Driven Engineering, Business Process Management System, Flexible Process Execution Activity [0] Task [3] Sub-Process [5] Call-Activity [4] Multi-Instance Parallel [6] Multi-Instance Sequential [7] Default [10] User [11] Script [12] Service [13] Receive [14] Expanded [11] Collapsed [12] Event-SubProcess [13] Gateway [1] Join / Split [3] Exclusive (XOR) [4] 1 function executeElements(iDataAddr, eInd) public2 if (msg.sender != (iDataAddr or this)) 3 throw 'REJECTED' 4 iFlowAddr = IData(iDataAddr).getIFlowNode(); 5 pState = IData(iDataAddr).getSubProcessState(); 6 queue = new Queue(eInd); 7 while(!queue.isEmpty()) 8 eInd = queue.pop(); 9 (preC, postC, typeInfo) = IFlow(iFlowAddr).find(eInd); 10 if (!isEnabled(preC, typeInfo, pState)) 11 continue; 12 removeTokens(pState, preC); 13 switch (typeInfo) 14 case PARALLEL_MULTI_INST: 15 for(i = 1 to IFlow(iFlowAddr).getCountInst(eInd)) 16 this.createInst(eInd, iDataAddr);

Smart Services for Energy Communities: Insights on Options and Priorities from a Multicriteria Mapping Study in Germany

“…Disrupting the execution of program code in any of these areas can compromise the integrity or availability of the blockchain system. In the design phase of this predisposition, we found two recent studies on the successful transformation of BPMN to Ethereum (Lopez-Pintado et al, 2019;López-Pintado et al, 2018), and none on the transformation of Hyperledger Fabric, which is a more technology-aware technology.…”

Which Event Happened First? Deferred Choice on Blockchain Using Oracles

“…Such process smart contracts need to implement the correct semantics of the original process model specification. Whether this is achieved using code generation (Weber et al, 2016;López-Pintado et al, 2019a;Ladleif et al, 2019) or interpretation (López-Pintado et al, 2019b) is secondary, as long as each source process concept is mapped to an equivalent smart contract concept. In practice, this mapping is a particular problem for external events and the deferred choice pattern-which we will elaborate on in the remainder of this paper.…”

“…In our own work, we implement conditional events to monitor local process data (Ladleif et al, 2019). Some approaches support constructs which can be used to emulate the behavior of external events, like service tasks in Caterpillar (López-Pintado et al, 2019a) or on-chain asset registries in Lorikeet (Lu et al, 2021). Weber et al (2016) discuss connecting to external services using a dedicated trigger component, which could also assume the role of a request/response oracle.…”

ICT-Driven Business Model Innovation in SMEs: The Role of Organizational Capabilities, Firm Size and Age

“…In the design phase of this predisposition, we found two recent studies on the successful transformation of BPMN to Ethereum (Lopez-Pintado et al, 2019;López-Pintado et al, 2018), and none on the transformation of Hyperledger Fabric, which is a more technology-aware technology.…”