Variable-State-Trigger: A Formal Model of Smart Contracts Based on Conditional Response and Finite State Automata and Its Application

Abstract

As one of the technical elements supporting the blockchain to realize decentralized autonomous organizations, smart contracts are crucial for understanding the inherent properties of blockchain systems through formal research. Most existing formal models of smart contracts focus primarily on static properties, lacking the depiction of dynamic processes such as conditional responses and internal state migration during contract execution, which complicates effective supervision. In this paper, a novel formal model of smart contracts, based on finite state automata, named Variable-State-Trigger (VST), is proposed, which presents state migration and conditional response mechanisms during smart contract execution. The VST model is verified to portray both the static and dynamic properties of smart contracts, providing new avenues for effective supervision during contract execution. Moreover, the VST model is used to illustrate the life cycle of a UAV mission smart contract, demonstrating its feasibility. With the growing integration of blockchain and emerging technologies, smart contracts have found applications in various fields, including drone swarm coordination. In this context, smart contracts enable secure, decentralized management and automation of interactions between autonomous drones, ensuring compliance with predefined conditions and enhancing the reliability of complex drone operations. The VST model can be extended to such applications, offering dynamic supervision and enhancing the coordination efficiency in decentralized autonomous drone systems.