1. Departement of Mathematics and Digital Society Initiative, University of Zurich, CH-8057 Zürich, Switzerland
2. UZH Blockchain Center, University of Zurich, CH-8050 Zürich, Switzerland
3. Blockchain & Distributed Ledger Technologies Group, University of Zurich, CH-8050 Zürich, Switzerland
4. DLT Science Foundation, London, United Kingdom
5. Physics Department, Università di Torino, I-10125 Torino and Istituto Nazionale di Fisica Nucleare, Italy
6. School of Informatics, University of Edinburgh, Edinburgh, Schotland, United Kingdom
7. IMT School for Advanced Studies Lucca, I-55100 Lucca, Italy