Alberto Garoffolo Dmytro Kaidalov Roman Oliynykov Zendoo: a zk-SNARK Verifiable Cross-Chain Transfer Protocol Enabling Decoupled and Decentralized Sidechains. 123 2020 2020 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2020/123 db/journals/iacr/iacr2020.html#GaroffoloKO20