Chapter 3: Review of Blockchain and Emerging Applications

A blockchain is a decentralized public ledger that uses cryptography to record transactions among a network's participating agents. A network using public (permissionless) blockchain consists of specific agents, and each transaction must be verified by an agreement, in most cases, among the majority of the agents. Once the transaction is entered into the system, the data on the chain are permanently stored and cannot be erased. Additionally, the information should be accessed using private and public keys held by the agents of a specific network. Each agent is assigned a private key, which is the equivalent of a password, for the agent's own information. An agent is also assigned a public key, which is an address that enables the agent to access specific information, comparable to an access code. A fundamental concept of the technology is that a transaction within a marketplace where participating members verify the transactions is more secure as well as time- and cost-efficient than any alternative. Because blockchain can be used across multiple applications, its flexibility is a major feature and an advantage of this prominent platform.