Blockchain, cross-chain, and multi-chain
In a cross-blockchain transaction, we assume that the transaction result can be a value transfer or the execution of a contract, and that:
• Underlying networks are secure with a concept of transaction finality within a finite time, after which the transactions cannot be rolled back.
• We loosely use “value” as a generic term to represent the cryptographic object that the blockchain carries.
• Security aspects such as double spending and 51
• We do not consider the semantics of data and exchange rate between two different tokens.