Preventing Interference in Smart Contracts

Abstract: Smart contracts are a new form of contracts that handle transactions of economical value between users on a network, without the need for a middle man. This is possible as the integrity of the transactions are ensured using Blockchain technology. However, safe transactions are not always a guarantee as secure smart contracts can be difficult to write. Security vulnerabilities in smart contracts can be exploited and result in great financial losses for contract users. In this report we examine how interference can be counteracted in transactions involving smart contracts. This is to ensure that assets of economical value do not run the risk of disappearing and that the flow of information between smart contracts remains truthful. The term "interference" is coined precisely in relation to smart contracts. Moreover, two different solutions for two interference problems are examined, which mainly involve locking the access to certain functions for specific contracts so that no modification of the state of one contract can take place until a transaction is finished. The methods for counteracting interference in the transactions work, but the solutions are adapted to the specific pr blems and do not serve as a "general" solution to the problem of interference.