  The booming Internet of Things (IoT) market has drawn tremendous interest
from cyber attackers. The centralized cloud-based IoT service architecture has
serious limitations in terms of security, availability, and scalability, and is
subject to single points of failure (SPOF). Recently, accommodating IoT
services on blockchains has become a trend for better security, privacy, and
reliability. However, blockchain's shortcomings of high cost, low throughput,
and long latency make it unsuitable for IoT applications. In this paper, we
take a retrospection of existing blockchain-based IoT solutions and propose a
framework for efficient blockchain and IoT integration. Following the
framework, we design a novel blockchain-assisted decentralized IoT remote
accessing system, RS-IoT, which has the advantage of defending IoT devices
against zero-day attacks without relying on any trusted third-party. By
introducing incentives and penalties enforced by smart contracts, our work
enables "an economic approach" to thwarting the majority of attackers who aim
to achieve monetary gains. Our work presents an example of how blockchain can
be used to ensure the fairness of service trading in a decentralized
environment and punish misbehaviors objectively. We show the security of RS-IoT
via detailed security analyses. Finally, we demonstrate its scalability,
efficiency, and usability through a proof-of-concept implementation on the
Ethereum testnet blockchain.
