## 4 Technical Solution
From a software platform perspective, the implementation of a circular economy can be identified mainly as an integration and data management problem that must be addressed with an articulated infrastructure capable of handling the three main phases of (1) data generation, (2) data provision, and (3) data consumption. Indeed, the actors of the circular supply chain must continuously share controlled streams of information related to the product and processes in order to optimize the real material, components, and product flows. As depicted in Figure 4, this paper proposes a platform that lays its basis upon the synergy between two of the main initiatives dedicated to integration and data management currently available at the European level: IDSA and FIWARE. On the peculiarities of the two reference architectures, the proposed infrastructure is designed to cover all of the key data management processes to ensure an efficient and secure exchange of knowledge among the players of the supply chain. At the data generation level, the actors of the supply chain must deal with a heterogeneous set of data sources that are different from each other in terms of format, accessibility interfaces, availability, and update frequency. Moreover, once collected, information must be harmonized and aligned, and must undergo the analysis process in order to produce high value-added knowledge. To this end, this paper proposes whenever possible the adoption of a FIWARE internal data collection and treatment layer. This layer, mainly represented by the Orion Context Broker, allows:  
* The integration, on the same data bus, of data streams coming from different sources thanks to the availability of IoT Agents capable of handling several different standard communication formats and mapping them onto a common representation of the process resources;
* The deployment of Data Apps, which are modules providing specific analysis, translation, and knowledge generation algorithms; these apps act as a bridge between the NGSI API of the FIWARE architecture and the security layer of the IDSA Internal Connector (INIC), exposing domain-specific data to the External Connector (EXIC) in a secure and controlled way. In order to provide a trusted set of Data APPS and in compliance with the IDSA specification, the platform envisions a common AppStore, whose main role is the certification of the Data Apps' behavior so that they can be safely deployed in the internal IT infrastructures of the suppliers. Examples of such data applications are the Sustainability App for the calculation of sustainability indicators, the Data Transformation Apps, whose objective is performing cross-format data translation, and the Big Data Apps for the analysis of big data streams coming from the field and the identification of relevant patterns. The FIWARE framework and the Data Apps represent the most internal and protected layers of the IDSA Internal Connector (INIC) that are responsible for the projection of each participant into the circular data space it belongs to. In fact, the second main aspect of data management is represented by the Data Provision. This phase requires identifying exactly what information should be shared with the other participants, who should be able to access it, and the expiration of the data in order to satisfy the data sovereignty principle. For this reason, the proposed platform, referring to the IDSA specification, relies on the adoption of an external connector (EXIC) component that, implementing the authentication and authorization control functionalities, protects access to internal data, providing a subset of information through an efficient p2p connection mediated according to the rules stored in the centralized Broker module.