Leveraging complex event processing for monitoring and automatically detecting anomalies in Ethereum-based blockchain networks

Blockchain is a relatively recent technology that provides immutability, traceability and transparency of information, thus building trust in the digital society. Blockchain networks generate a large amount of logs which capture and describe data flowing through the network in the form of transactions, blocks and events. Monitoring these blockchain data from the off-chain world is needed to detect anomalies with the aim of mitigating the risks that may arise as a result of using blockchain technology. However, the realtime monitoring of these logs by off-chain systems has become a challenge from the beginning of 2018 when the blockchain networks reached a high number of daily transactions. In this paper, we propose a portable, maintainable and easily configurable architecture integrating blockchain and complex event processing technologies that allows for both the real-time monitoring of logs generated in Ethereum Virtual Machine (EVM)-compatible blockchain networks and the automatic detection of anomalies in these networks by matching event patterns. This architecture was tested by using vast amounts of blockchain data already publicly registered in Ethereum and Polygon networks. The results demonstrate that the proposed architecture is able to automatically detect anomalies which occur in different blockchain networks, making analytics of blockchain data possible by off-chain systems.