The BloG³ project tackles the fragmentation of patient‑related health information that arises when data are collected by many different institutions and stored in heterogeneous systems. The goal is to give patients a transparent, patient‑centric view of their own data even when those data are stored in a decentralized fashion. To achieve this, the consortium is building a digital platform that combines a blockchain‑based decentralized data and access‑rights management system with an ecosystem that integrates representative German systems for treatment, discharge, and after‑care management. A patient‑facing application will serve as the interface for viewing and sharing data, allowing patients to decide which information they share with which actors in their network.

The technical work of the Karlsruhe Institute of Technology (KIT) focuses on the architecture of the BloG³ platform. KIT’s responsibilities include selecting an appropriate distributed ledger technology (DLT) as the foundation of the blockchain, gathering requirements for both the individual subsystems and the overall system, and ensuring that the design supports high levels of user acceptance. The chosen DLT is based on the Ethereum protocol, which uses a proof‑of‑work consensus mechanism. The platform is designed to guarantee that every data record can be uniquely linked to a single patient, even when the data originate from external systems. Data integrity and access control are enforced by the immutable ledger, while the patient app provides a user‑friendly gateway to the underlying blockchain.

During the project, KIT built a demonstrator and evaluation environment that integrates the various subsystems into a single, coherent system. The demonstration was used to test the technical feasibility of the architecture and to conduct user studies that assess the system’s acceptability from the perspectives of patients, clinicians, and other stakeholders. The evaluation also examined incentive mechanisms that could encourage continuous use of the platform. While the report does not provide explicit performance metrics such as transaction throughput or latency, it reports that the platform was successfully deployed and that the user studies indicated a positive reception of the blockchain‑based approach. The system’s ability to maintain a consistent, tamper‑proof record of patient data and to provide fine‑grained access control is highlighted as a key technical achievement.

Collaboration in BloG³ is organized around several work packages. KIT serves as the interface partner, coordinating the architecture design and integration tasks. The Freie Universität Berlin (FUB) leads the transfer and exploitation work package, focusing on scaling the solution to oncology and other clinical areas and on developing a service‑innovation ecosystem. Other partners contribute to the development of the patient app, the integration of legacy systems, and the analysis of governance implications. The project runs within the broader BloG³ consortium, which is funded by the European Union under the Horizon 2020 programme. The consortium’s timeline spans several years, with the KIT’s contributions covering the design, implementation, demonstration, and evaluation phases. The collaborative effort aims to produce a reusable, patient‑centric platform that can be adopted across the German health system and potentially beyond.