ZetaChain is first of all a public blockchain with Proof-of-Stake validators. It’s trusted that a super majority (>66% nodes) of the validator nodes are honest and act according to protocol, and collectively serve as notaries. In addition to being a blockchain, interoperability requires observing other blockchains. Thus each ZetaChain validator node is attached with an observer that scans other blockchains for relevant events (event log, transaction, or state at a certain time). The observers...