Design and Implementation of an IDPS for the Blockchain Network

Blockchain is widely adopted by decentralized applications for the strong security guarantees it offers, enabling trusted exchange of transactions in fully distributed peer-to-peer networks. These security guarantees, ideally, prevent malicious actors from manipulating or forging the distributed ledger in which the transactions are stored. However, the lack of content validation allows attackers to append formally valid transactions that contain malicious code, intended to exploit blockchain software vulnerabilities, to the ledger. As a result, several blockchain implementations have suffered from huge amount of monetary losses and compromises that undermined their security features and guarantees. In this thesis, we propose a signature-based collaborative blockchain intrusion detection system, BID, that enables all nodes in the network to detect and prevent the execution of malicious transactions without disrupting the underlying consensus protocol. The system provides the network with a trusted, immutable, unified, up-to-date view of the signature-database hence avoiding hard forks and ensuring the security of each node. We introduce BID from a design perspective and provide a prototype implementation based on the Ethereum platform, which demonstrates the feasibility of our approach. In particular, the introduced overhead in our Proof of Concept is already quite viable---while code and algorithmic optimization could further reduce it.