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, and thus, must be propagated to partners affected by the change. In this paper, we propose an 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 blockchain-based DCR choreography instance to change its private process. A change impacting other partners is propagated to their processes in a decentralized manner using a SC. The change propagation mechanism ensures the compatibility checks between public processes of the partners and the consistency between the private and public processes of one partner. We demonstrate the approach’s feasibility through an implemented prototype and its effectiveness via a set of evaluation tests.

Smart Contracts (SC for short) are gaining momentum as a suitable technology for ensuring trusted execution of Business Processes (BP for short) in open environment. Nevertheless, the transactional semantics of SC which follow ACID transactions are not appropriate for BP characteristics. Indeed, it is admitted that ACID transactions are limited to cope with complex control structure and long running execution of BP. Transactional Business Processes (TBP for short) have emerged as an extension to ACID models to overcome these limits. A TBP ensures transactional reliability of advanced transactions having a control structure as complex as for BP. In this paper, we propose an approach that builds on SC and extends them to implement TBP. We extend Caterpillar, an existing BP execution engine developed on top of Ethereum, to implement our approach and support the execution of TBP.

Blockchain trends cover more and more tech domains making it one of the most used technologies in the last few years. This is due to two essential aspects. First, it is a distributed peer-to-peer network where there is no need for third part to execute operations between peers. Second, blockchain implements mechanisms to make the most data sensitive operations executed in a trusted way. Regarding these attractive aspects, we intend in this work to use the blockchain technology for the implementation of touristic itineraries. We consider the latter as process choreographies involving different participants. We intend to model and execute the touristic itineraries generated from a personalized trip planner called CART in raw XML format in a way that respects this collaborative aspect and resolves the problem of trust. We will propose a pattern and its transformation rules to reconstruct the itineraries presented in declarative annotations such as XML to smart contracts written in some smart contract-specific programming language called Solidity. Experimental results show promising perspectives of the deployment of the proposed solution to execute touristic plans.