Engineering Trustable and Auditable Choreography-based Systems Using Blockchain

A key challenge in engineering distributed systems consists in the integration into their development of a decentralised infrastructure allowing the system participants to trust each other. In this article, we face such a challenge by proposing a model-driven methodology and a related framework to support the engineering of trustable and auditable systems. The approach is based on choreography diagrams specified in the Business Process Model and Notation standard, describing the interactions that should occur among the distributed components of systems. We support the whole lifecycle of choreographies, from their modelling to their distributed execution and auditing. The framework, based on blockchain technology, is named ChorChain. More specifically, ChorChain takes as input a BPMN choreography model and automatically translates it into a Solidity smart contract. The smart contract permits us to enforce the interactions among the cooperating components as prescribed by the choreography model. By leveraging on the auditability of blockchain ChorChain also supports the activity of auditors continuously. In such a way, ChorChain enables auditors to get some degree of assurance on what happens simultaneously with, or shortly after, information disclosure. We assess the feasibility and effectiveness of the proposed methodology and framework through experiments conducted on the Rinkeby Ethereum Testnet.