Bitcoin, blockchains, and cryptocurrencies are fascinating to me because there are so many elements to understand. This multidisciplinary nature is one of the reasons I, and so many others, love the industry—it is easy to get sucked into the rabbit hole, and as you try to understand each element, every answer begets more questions. The journey starts with ‘What is Bitcoin?’ but the explanations and answers come from the disciplines of economics, law, computer science, finance, civil society, history, geopolitics, and more. You could create a pretty comprehensive high school curriculum around Bitcoin and have plenty of material to spare.
And this is the very reason why it is so hard to explain. This book is an attempt to cover the basics. It is aimed at the thinking person but assumes that the reader doesn’t have a detailed background in the various disciplines mentioned previously. Different people will find different parts interesting. I try to use analogies where I think they help explain some concepts, but be gentle with me: all analogies break down if stretched too far. And although I have tried to be accurate, there will still be oversimplifications, errors and omissions. What is true today may not be tomorrow: the pace of change is rapid. I am the first to admit that there are limits to my own technical expertise. Nevertheless, I hope that every reader comes away learning something new.
With that, let’s start by defining at a basic level some of the words and concepts we will be exploring later in the book.
Bitcoin1 and Ether are two of the better-known cryptocurrencies or coins (note that the coin on the Ethereum network is called Ether, though is often misnamed in the media as ‘Ethereum’). These are assets or items of value that exist digitally, not physically, and are created by software. They have no issuer as such. No person, company, or entity backs these, and there are no terms of service or guarantees associated with them. Like physical gold, cryptocurrencies simply exist, and are created or destroyed according to the rules articulated in the code that creates and governs them. If you own some cryptocurrency, and we’ll see what that actually means later, it is your asset that you control. It has value, and can be exchanged for other cryptocurrencies, US dollars, or other global sovereign (or fiat) currencies. Its value is determined within marketplaces called exchanges where buyers and sellers come together to trade at mutually agreed prices.
As well as ‘coins,’ units of cryptocurrencies may be described as digital assets. That is, unique data items whose ownership can be passed from account to account. These accounts are technically called addresses, and we will explore what addresses are later. When these digital assets move from one account to another they are all recorded on their respective transaction databases known, because of some unique shared characteristics which we will look into later, as blockchains.
Just to confuse everybody, some digital assets are described as tokens, as in ‘Is it a cryptocurrency or a token?’. Cryptocurrencies and tokens are both types of cryptographically secured digital assets, sometimes known as cryptoassets. These tokens have different characteristics from cryptocurrencies and from each other. Tokens can be fungible (one token being more or less replaceable by another), or non-fungible (where each token represents something unique). Unlike cryptocurrencies, these newer tokens are usually issued by known issuers who stand behind them, and the tokens can represent legal agreements (like financial assets), physical assets (like gold), or future access to products and services.
Where the underlying item is an asset you could think of the token as a digital version of a cloakroom ticket, issued by a cloakroom clerk and redeemable for your coat. Indeed, these tokens are sometimes called DDRs—Digital Depository Receipts. Where the underlying item is an agreement, product or service, you can think of the token as something like a concert ticket issued by a concert organiser and redeemable for entry to a concert at a later date.
To give some real examples, there are tokens that represent everything from gold bullion sitting in a vault somewhere2, through to tokens representing unique ‘CryptoKitties’—collectable digital cats with specific visual attributes determined by their ‘DNA’ code.