Coordinating REST Interactions in Service Choreographies using Blockchain

In Service Oriented Computing (SOC), different services interact and ex- change information to reach specific objectives. To model inter-organizational SOC systems, Choreography modeling languages emerged to represent the distributed coordination among the involved organizations. From the real- ization perspective, blockchain technology is emerging as a promising run- time supporting peer-to-peer communication without the need for a central coordinator, thanks to its intrinsic security, trust and decentralization char- acteristics. However, while blockchain can bring many advantages, techno- logical barriers still limit its adoption in organizations, due to the costly and time-consuming learning process. For this reason, we propose RESTChain, a framework enabling in an automatic way the interactions that take place among the participants in a service choreography exploiting blockchain tech- nology. Starting from a choreography specification, the framework provides a set of Mediators and automatically generates a Smart Contract that co- ordinates the service interactions. The mediators are software components that are directly connected with the smart contracts and expose REST APIs in compliance with the role played by the organizations in the choreography. In this way, the services deployed by one organization can communicate with the services made available by another organization through the blockchain, in a secure and transparent manner. The proposed approach has been im- plemented on the Layer 2 Polygon blockchain and has been validated on a Market Retail case study analyzing its efficiency in terms of costs and times.