Common use of Blockchain Clause in Contracts

Blockchain. A blockchain is a decentralized and append- only database, consisting of blocks, which are appended periodically after consensus. Each block contains a number of transactions, which are validated by miners and stored by full nodes. Denote itv as the block interval, i.e the time interval between two contiguous blocks. Note that itv varies in a small proportion, the average of which is close to a preset value defined in the blockchain system, which is ensured by a consensus algorithm. For example, the preset block interval of Bitcoin [17] is 10 min, while Ethereum [18] has a 15 sec interval. This brings the definition of latency. Denote T as the time when a user submits a transaction to a blockchain, and C as the time when the transaction is included in a block, then C T is the confirmation delay for this transaction, or the latency. One can see that by definition, C T can also be roughly expressed as n itv, where n stands for the number of blocks passed by. Each block has a capacity limit because a larger block usually brings additional network latency during consensus, which increases the chance of forks and causes less performant full nodes to gradually loose its ability to keep up with the network due to space and speed requirements. Since block capacity is limited, the latency issue occurs when the blockchain system is overwhelmed by transactions. Only TABLE I NOTATIONS TX Transaction x Input of f S Vector of S, transited by f S′ Vector of S, the transition result of f c = (hstate, hinput) Commitment U, c, d Vectors of corresponding items involved in a transaction a tremendous amount of time to validate, making the users suffer from the latency issues.