Cross-chain Bevakning av Övergripande Egenskaper i Smart Contracts : Användning av affärsspecifikationer för att modellera interaktioner mellan smarta kontrakt på olika blockchains

Smart contracts are programs that reside on a blockchain such as Ethereum, which self-execute when certain conditions are met. As with all things that utilize blockchain technology, a key aspect of smart contracts is the immutability of both the code and the execution. This immutability, while making smart contracts a powerful tool for decentralized applications also brings new issues when programs are faulty, as updating them is nontrivial, and vulnerabilities often lead to significant financial losses. Some smart contracts facilitate transactions between different blockchains, further increasing the complexity of verifying them. In this paper, we extend the open-source blockchain monitoring tool HIGHGUARD to support cross-chain runtime monitoring of smart contracts by using a business process notation as a model and cross-checking each transaction against it. We show that a model-based monitoring approach can be effectively applied to detect certain vulnerabilities in cross-chain applications.