A Metric-Based Approach to Modelling a Virtual Machine for Smart Contract Execution

Applicability of smart contracts showed significant potential to multiple industries by offering data integrity, transparency, non-repudiation, and trust automation. An essential part of programmability within a blockchain is a process virtual machine that performs the execution and outputs new valid states. In this paper, there will be proposed theoretical models that address the problems that arise in the design of a virtual machine in blockchain, by strongly emphasizing the importance of metrics for an efficient halting mechanism. A model aimed towards performing computations and tracking state changes will be presented in order to discuss the key aspects of programmability in blockchains. Also, the virtual machine will be defined as a deterministic state automaton and within the definition, additional metrics for a halting condition will be proposed. We also propose a loosely-coupled architecture such that the virtual machine's interactions with the blockchain are handled in an isolated manner from the blockchain's functionality and also introduce an additional layer on top of the virtual machine designated to add privacy and improve scalability.