HELENE: An Open-Source High-Security Privacy-Preserving Blockchain Based System for Automating and Managing Laboratory Health Tests. - Gabriel Fernández-Blanco; Pedro García-Cereijo; David Lema-Núñez; Diego Ramil-López; Paula Fraga-Lamas; Leire Egia-Mendikute; Asís Palazón; Tiago M. Fernández-Caramés (CoRR, 2025)