Long-Term Blockchain Transactions Spanning Multiplicity of Smart Contract Methods

Research on blockchains addresses multiple issues, with one being writing smart contracts. In developing smart contracts, blockchains have complex constraints that complicate the design and development of smart contracts, software that controls the blockchain transactions. Blockchain applications that involve collaborations of multiplicity of actors, such as in trade of goods and services, give rise to additional complexity in that transaction activities tend to be long term, perhaps hours or days, and thus spanning multiplicity of methods of a smart contract. The problem is that a block-chain only supports the concept of a transaction within the scope of an execution of a single smart contract method. We compare the requirements and properties of long-term transactions and blockchain transactions and examine their mismatch. We then propose how to represent long-term blockchain transactions in smart contracts, and we describe a mechanism to support such transactions using patterns. Finally, we evaluate the proposed mechanism in terms of supporting transactional properties and its cost of execution.