Frauenthaler, PhilippPhilippFrauenthalerSigwart, MartenMartenSigwartBorkowski, MichaelMichaelBorkowskiHukkinen, TaneliTaneliHukkinenSchulte, StefanStefanSchulte2022-04-042022-04-042019Whitepaper, Technische Universität Wien (2019)http://hdl.handle.net/11420/12191Interoperability between blockchains remains an open problem, with current interoperability approaches provid- ing very limited means of cross-blockchain interaction, mostly in the form of atomic swaps. More general means of blockchain in- teroperability such as cross-blockchain data exchange, including cross-blockchain token transfer would contribute to dissolving today’s fragmentation of the research and development field of blockchains. To address this issue, within the TAST research project, a cross-blockchain token was developed. However, the developed solution suffers from high synchronization cost. In this paper, we discuss requirements for more efficient cross- blockchain token transfers, describe open research challenges, and give an outlook on two approaches aiming to overcome these challenges.enAllgemeines, WissenschaftResearch Reporthttps://dsg.tuwien.ac.at/tast/tast-white-paper-5.pdfOther