# Integrating Blockchains with the IoT: A Review of Architectures and Marine Use Cases
## 4 Applications and Challenges of Blockchains in MIoT and IoUT
### Digiacco  
In this section, the DIGI4 ECO [47] project is briefly described as an indicative large-scale technological use case that is aligned with the framework of the present article. The full title of the project is \"Digital Twin-sustained 4D Ecological Monitoring of Restoration in Fishery Depleted Areas\", The project is funded by the European Commission with a duration from 2024 to 2028, while the consortium consists of 18 participants. DIGI4 ECO is linked with the \"integration of biodiversity monitoring data into the digital twin ocean\" topic, which is related to the European Green Deal and the Biodiversity Strategy. At a broad level, the projects funded under this topic aim to increase the collection of ocean datasets focusing on biodiversity, including on species, habitats, and ecological interactions. These efforts are expected to tackle the deterioration of coastal and marine ecosystems, such as degraded seabed habitats, and will contribute to developing and demonstrating protection and restoration strategies to enhance and safeguard the EU's blue natural capital. The objective of the DIGI4 ECO project is to enable new discoveries that are crucial for addressing climate change and regulating human activities, both of which are vital for environmental conservation and socio-economic development. DIGI4 ECO aims to make biological and oceanographic data accessible to the public, addressing past, present, and future data points. To accomplish this, the project will utilize existing, under-explored datasets by developing innovative tools and methodologies for processing data previously collected by various entities. The sources of this data are quite diverse, ranging from physical and chemical sensors to video cameras. In addition, DIGI4 ECO seeks to harmonize and standardize the relevant data, utilizing tools that facilitate their use by researchers and data generators. In this context, the project aims to ensure secure and reliable data flows by developing automated correction and validation methodologies. Furthermore, leveraging economies of scale and enhanced standardization, DIGI4 ECO will conduct large-scale monitoring tests across sea basins, applying two strategies: the utilization of existing datasets from online and partner repositories and the collection of new data during field demonstrations. Through these efforts, DIGI4 ECO will develop tools to enhance environmental assessments by identifying key indicators and extracting them from the data, supporting decision-making by policymakers, researchers, and socio-economic sectors. By making these methodologies and tools open-source, the project aims to promote widespread adoption and continued development, ensuring a lasting impact beyond its completion. The overall DIGI4 ECO platform is a complex system composed of various technologies, ranging from highly specialized sensors to data analytics and machine learning. The blockchain component is positioned near the modules responsible for collecting and processing relevant data. It serves as a middleware between data creators and consumers, with its primary mission being to secure and control access to data by leveraging the foundational properties of blockchain technology. Specifically, the DIGI4 ECO blockchain component was designed with a modular structure, consisting of three key sub-components, the frontend, backend, and aux, each responsible for specific operational roles to ensure seamless and reliable blockchain interactions. The frontend acts as the main communication interface for other DIGI4 ECO components, functioning as a stateless web service. It receives and processes blockchain-related requests independently, forwarding them to the backend for execution while also coordinating with the aux component as needed. The backend, centered around blockchain operations, utilizes Hyperledger Besu, an open-source Ethereum client under the Apache 2.0 license.