Blockchain Validity Register for Healthcare Environments Cinthia Paola Pascual Cáceres, José Vicente Berná Martinez (B ) , Francisco Maciá Pérez, and Iren Lorenzo Fonseca University of Alicante, San Vicente del Raspeig, Alicante, Spain cppc2@alu.ua.es, {jvberna,pmacia}@dtic.ua.es, iren.fonseca@ua.es Abstract. Currently, health information systems are decentralised and hypercon- nected to third-party data sources and systems. For their proper use, they require adequate security measures to verify the validity of information, thus avoiding potential harm to patients using erroneous, corrupt or altered data. These systems must be able to avoid vulnerabilities to decentralisation, prevent record modi- fication and data integrity problems, and facilitate fast and efficient verification operations, since it is very important that security mechanisms must not hinder the operation of these systems on which human lives depend. In this paper, we propose a decentralised registry system for healthcare environments based on Blockchain technology. This register can provide the same security as transaction registers in distributed databases, but allows for load balancing as it is a decentralised system, thus facilitating fast and efficient operations, and provides Blockchain mechanisms to maintain the integrity of the validation register. Keywords: Security · Data veracity · Blockchain · Health system 1 Introduction Today’s healthcare systems have evolved from the electronic medical record, in which a patient’s clinical information was stored digitally in a single medical centre, to the elec- tronic health record, where all of a patient’s medical information is stored in a distributed manner throughout the healthcare system so that it can be accessed and shared through different specialised tools [1]. Modern environments are made up of different medical centres such as hospitals, neighbourhood health centres, mobile systems, emergency departments and laboratories, among others. Each of them collects, stores and processes the information associated with the patients seen daily in these centres, and this informa- tion is stored in decentralised databases that ensure the availability, confidentiality and integrity of the data, while at the same time having to reconcile all this heterogeneous and distributed data flow [2]. In addition, new devices that collect data about patients and their environment through IoT-based technologies have been incorporated into the medical system [3]. The aim of these devices is to achieve more effective treatments and savings in health- care through more comprehensive patient monitoring, but at the same time they lead to © The Author(s), under exclusive license to Springer Nature Switzerland AG 2022 J. Prieto et al. (Eds.): BLOCKCHAIN 2021, LNNS 320, pp. 64–73, 2022. https://doi.org/10.1007/978-3-030-86162-9_7