Universal Payment Channels: An Interoperability Platform for Digital Currencies. - Mihai Christodorescu; Erin English; Wanyun Catherine Gu; David Kreissman; Ranjit Kumaresan; Mohsen Minaei; Srinivasan Raghuraman; Cuy Sheffield; Arjuna Wijeyekoon; Mahdi Zamani (CoRR, 2021)