Dany: scalability solutions for IoT smart contracts

Smart contracts are self-executing programs that run when certain predetermined conditions are met. The advent of blockchain technologies provided the means to executing smart contracts in a decentralized fashion without the need of trust- ing a central authority: the correct execution of the smart contract is ensured by the consensus protocol of the blockchain on which it is deployed. Blockchain smart contracts property of trustless execution make it an interesting technology for the IoT. However, IoT applications often require processing large amounts of data which are often difficult to manage in a blockchain environment. In fact, traditional blockchains can process only few transactions per second, making it unsuitable for the needs of many IoT applications. Furthermore, traditional pub- lic blockchains require users to pay fees for every piece of data committed to the chain, this makes the use of blockchains too expensive in many IoT case scenarios, since they often involve IoT devices exchanging large amounts of messages. In this thesis, it is presented a solution for executing smart contracts that improves scalability on blockchains in terms of throughput and costs. The solution is par- ticularly suited for the IoT but its generality make it possible to be used in a variety of scenarios not necessarily related to the internet of things.