Security and Privacy for Hybrid Centralized and Blockchain Computing in the Internet of Things******

物联网（IoT）是物理对象、传感器、执行器、计算机和人的全球网络集合。研究物联网预测可以得出两个结论：1)物联网领域预计将继续以每年约20%的速度增长；2)物联网最大的风险是安全性、可扩展性和可靠性。以这样的增长速度推进，将安全作为主要风险是一个站不住脚的解决方案。虽然业界将继续开发新产品和短期解决方案，但需要进行基础研究，为物联网网络和设备建立安全高效的基础。网络的复杂性、大量数据、实时访问数据的需求、有限的资源和设备的移动性，使得物联网系统的安全和隐私机制的实施极具挑战性。目前还没有一种集中式安全机制能够满足大规模物联网系统的所有要求。区块链是2008年为比特币加密货币引入的去中心化点对点（P2P）分类账。值得注意的扩展包括以太坊智能合约，它为互不信任的实体之间提供安全计算机制。区块链技术提供可信共识和数据处理的能力正在迅速引起人们对潜在物联网应用的兴趣，但必须首先克服基本挑战。本研究的目标是开发新型混合集中式和区块链网络，将区块链的优势带入物联网系统。我们将通过硬件和软件中的创新架构、协议和原型实现来实现这一目标。这项研究将有助于提高关键基础设施对网络攻击的抵抗力，并将通过为物联网中基于区块链的系统创建安全基础，加速依赖物联网网络和设备的新应用的开发。

The Internet-of-Things (IoT) is a world-wide collection of networks of physical objects, sensors, actuators, computers, and people. Two observations emerge from studying IoT predictions: 1) the IoT sector is predicted to continue to grow by approximately 20% per year, and 2) the greatest risks for IoT are security, scalability, and reliability. Proceeding at this rate of growth with security as a major risk is an untenable solution. While industry will continue to develop new products and short-term solutions, fundamental research is needed to develop a secure and efficient foundation for IoT networks and devices. The complexity of the networks, large volume of data, need for real-time access to data, and constrained resources and mobile nature of devices make it extremely challenging to implement security and privacy mechanisms for IoT systems. No known centralized security mechanism satisfies all of the requirements of large-scale IoT systems. A blockchain is a decentralized peer-to-peer (P2P) ledger introduced for the Bitcoin cryptocurrency in 2008. Notable extensions include Ethereum smart contracts, which provides mechanisms for secure computation between entities that do not trust each other. Blockchain technology's ability to provide trusted consensus and data processing is rapidly generating interest in potential IoT applications, but fundamental challenges must first be overcome. The goal of this research is to develop novel hybrid centralized and blockchain networks that will bring the benefits of blockchains to IoT systems. We will achieve this goal with innovative architectures, protocols, and prototype implementations in hardware and software. This research will help make critical infrastructure more resistant to cyberattacks and will accelerate development of novel applications that rely on IoT networks and devices, by creating a secure foundation for blockchain-based systems in the Internet of Things.