The lack of intrinsic security technologies in the current Internet of Things (IoT) systems brings forth numerous security vulnerabilities and privacy risks. To this end, a distributed and decentralized technology named blockchain comes out as a viable solution. This paper investigates the integration trends of blockchain technology with IoT and discusses the insights of this new paradigm. In particular, this paper presents a comprehensive survey on security improvements achieved in IoT systems using blockchain and the challenges that originate during this integration. Further, the paper highlights the most relevant blockchain based IoT applications and outlines some future research directions.

当前的物联网（IoT）系统缺乏内在的安全技术，带来了许多安全漏洞和隐私风险。为此，一种名为区块链的分布式，去中心化技术应运而生。本文研究了区块链技术与物联网的集成趋势，并讨论了这种新范式的见解。特别是，本文针对使用区块链的物联网系统中实现的安全性改进以及集成过程中带来的挑战，进行了全面的调查。此外，本文重点介绍了最相关的基于区块链的物联网应用程序，并概述了一些未来的研究方向。