The combination of blockchain technologies and Internet of Things devices on a network reduces overall network usage by centralizing communication that is broadcasted to all devices via a server. A blockchain-based key management protocol lessens the need for a centralized key authority while retaining similar security compared to its centralized counterpart.

Introduction

Internet of Things (IoT) devices, like a smart-speaker or smart-thermostat, are typically low-processing power and low-memory computers that interact with each other on a network. Blockchain was first introduced by S. Nakamoto as a secure transaction ledger for a new cryptocurrency known as Bitcoin. A blockchain is a sequence of blocks that contain transactions, or messages in the case of IoTs. Blocks are added to the blockchain through a mining process which takes a significant amount of processing power to compute a valid block that is deemed acceptable by the network. Blockchain technology is created in a way that limits the ability to alter a blockchain and its contents by sheer processing power. The only way to take control of the blockchain is through a theoretical 51% attack, where an attacker must have at least 51% of the computational power on a blockchain in order to alter block contents and validate it faster than all other combined users on the network. This paper is organized as follows. Section II describes others’ research work in terms of IoT devices and blockchain. Section III discusses a blockchain framework implementation. Section IV establishes a key management protocol using the blockchain framework of the previous section. Section V refers to the blockchain parameter updates for dynamic IoT environments. Section VI briefly discusses the possibility of secure data transmission using the blockchain by storing temporary public keys for mutual session key generation. Section VII analyzes the proposed equations, the blockchain, and the difficulty parameter used throughout the paper. Section VIII analyzes the different hashing algorithms from the SHA-3 library for blockchain purposes. Section IX provides a summary and a few closing remarks as a conclusion to this paper.