A Trustworthy decentralized Change Propagation Mechanism for Declarative Choreographies

Abstract

Blockchain technologies have emerged to serve as a trust basis for the monitoring and execution of business processes, particularly business process choreographies. However, dealing with changes in smart contract-enabled business processes remains an open issue. For any required modification to an existing smart contract (SC), a new version of the SC with a new address is deployed on the blockchain and stored in a contract registry. Moreover, in a choreography, a change in a partner process might affect the processes of other partners. Thus, the change effect must be propagated to partners of the choreography affected by the change. In this paper, we propose a new approach overcoming the limitations of SCs and allowing for the change management of blockchain-enabled declarative business process choreographies modeled as DCR graphs. Our approach allows a partner in a running blockchainbased DCR choreography instance to change its private DCR process. A change impacting other partners is propagated to their affected processes using a SC. The change propagation mechanism ensures the compatibility checks between public DCR processes of the partners. We demonstrate the approach's feasibility through an implemented prototype.

Declarative Choreographies with Time and Data

“…It is important to mention that in all the works cited (1) the guarantees for communication are expressed in terms of safety properties, thus liveness is not considered, and (2) the constructs for continuation are defined in terms of imperative flows, contrasting to continuations based on may/must relations such as those existing in DCR graphs. DCR choreographies have been used to monitor change requests in blockchains [4]. As our work presents an orthogonal extension to the control flow relations used in [16], we believe that monitors such as that in [4] will benefit from an additional expressive power where data and time constraints can be expressed.…”

“…DCR choreographies have been used to monitor change requests in blockchains [4]. As our work presents an orthogonal extension to the control flow relations used in [16], we believe that monitors such as that in [4] will benefit from an additional expressive power where data and time constraints can be expressed.…”

“…For simplicity, we will not consider explicit dates in expressions, however, this is supported in the process engine available for free academic use at dcrsolutions.net 4. specified as P7D in the ISO 8601 standard…”