Off-Chain Execution of IoT Smart Contracts

Modern blockchains allow the definition of smart contracts (SCs). An SC is a computer protocol designed to digitally ease, verify, or enforce the terms of agreement between users. SCs execution can require high fees when lots of computation is required or a high volume of data is stored. This is usually the case of Internet-of-Things (IoT) systems where a large amount of devices can produce a high volume of data. Off-chain contract execution is a viable solution to decrease the blockchain fees. Users can agree on an on-chain SC which is stored in the main chain. Computation can then be moved securely outside the chain to reduce fees. In this paper we propose DIVERSITY a novel approach that allows off-chain execution of SCs. DIVERSITY provides a novel model for defining on-chain contracts that can be securely executed by using a novel off-chain protocol. We have validate our approach on a novel IoT case study where fees have been greatly reduced.