  An Intrusion Detection System (IDS) aims to alert users of incoming attacks
by deploying a detector that monitors network traffic continuously. As an
effort to increase detection capabilities, a set of independent IDS detectors
typically work collaboratively to build intelligence of holistic network
representation, which is referred to as Collaborative Intrusion Detection
System (CIDS). However, developing an effective CIDS, particularly for the IoT
ecosystem raises several challenges. Recent trends and advances in blockchain
technology, which provides assurance in distributed trust and secure immutable
storage, may contribute towards the design of effective CIDS. In this poster
abstract, we present our ongoing work on a decentralized CIDS for IoT, which is
based on blockchain technology. We propose an architecture that provides
accountable trust establishment, which promotes incentives and penalties, and
scalable intrusion information storage by exchanging bloom filters. We are
currently implementing a proof-of-concept of our modular architecture in a
local test-bed and evaluate its effectiveness in detecting common attacks in
IoT networks and the associated overhead.
