## 2 Challenges  
For European manufacturing to leverage competitive circular economy advantages, the industry at large must face the digital transformation process, addressing the digitalization of agile and sustainable value networks, towards a data-driven circular-economy-based production. However, several challenges are still standing for the next generation of a B2B platform for a fully digital industry and value chain, having a direct impact on the implementation of circular principles at the company and network levels [10]:  
_Challenge 1--The silo effect has not been actually relieved, and interfaces are only partially developed_[11]. Information silos occur whenever a data system is incompatible or not integrated with other data systems (at the technical architecture level, at the application architecture level, or at the data architecture level). According to the London School of Economics, this is one of the greatest stumbling blocks that companies identify in their attempts at better utilizing data. The causes are numerous: inconsistency in the systems being used, different data formats, lack of a coordinated data strategy, lack of technology integration, and legacy technology barriers. The silo effect hampers data exchange between companies belonging to the same circular value network. This results in a twofold challenge to circular economy practices: on the one hand, the effective resource and service sharing required by industrial symbiosis is hindered by the corresponding lack of data sharing; on the other hand, the optimization of products' lifecycles and the generation of Product Service Systems (PSS) need data concerning different product lifecycle phases to seamlessly flow within a single organization and along the entire value network. _Challenge 2--Too many overlapping standards and vendor-specific platforms make interconnections laborious_[12]. Standards are key enablers in manufacturing. Standards provide data definitions, detailed models of the information relationships, and interface protocols for the product and process lifecycles. They support product designs and management, production system design and operations, and integration into business value chains. These are the foundations on which information can flow throughout the levels of manufacturing control and between partners in a manufacturing enterprise, including the various software vendors and devices. Overlap between standards is caused both by the differences among regional, national, and international standards systems, and by the fact that standards in the same technical areas, but in different application sectors, are defined independently (e.g., material-testing methods defined for different industry sectors are often not consistent). CE approaches stimulate companies to break down barriers with suppliers and partners that, especially in this context, may belong to either geographically or sectorally remote industries. The players of the circular value chain may thus refer to different standards and data-management platforms, restricting the possibility to connect them and let them work on a shared value. Challenge 3--Lack of secure exchange of data and clear data ownership[13]Fundamental data security must deal with several challenges, such as data tampering, eavesdropping and data theft, falsifying user identities, password-related threats, unauthorized access, and lack of accountability. As far as ownership is concerned, existing liability laws are based on the concept of tangible products. Companies cannot be sure whether they can recourse to this legislation for data, so they prefer to fall back on contractual liability on a case-by-case basis, and not on the potential that new technologies offer.