An overview of Ethereum

In late 2013, Vitalik Buterin sent an email to the blockchain community announcing a white paper outlining the idea for Ethereum. He described it as a universal platform with internal languages, so anyone could write an application. According to Vitalik, the original idea for Ethereum was to create a general-purpose blockchain for fintech. Ethereum is a variation on Bitcoin. Unlike Bitcoin, which is a blockchain focusing on payments, Ethereum is a programmable, general-purpose blockchain. The introduction of smart contracts is the key to differentiating Ethereum from Bitcoin.

A well-known analogy to describe Ethereum and smart contracts, which bring together untrusting parties trading digital or digitized physical assets, is a vending machine, as described at the end of Chapter 12, Introduction to Blockchain Technology. 

After a vending machine is made, nobody, including the machine owner, can change the rules. A buyer does not need to worry about the owner altering...