What Is Bitcoin?
In 2008, a pseudonymous programmer named Satoshi Nakamoto published a 9-page document outlining a new decentralized, digital currency. They called it Bitcoin.
Bitcoin is the world’s first successful decentralized cryptocurrency and payment system, launched in 2009 by a mysterious creator known only as Satoshi Nakamoto. The word “cryptocurrency” refers to a group of digital assets where transactions are secured and verified using cryptography – a scientific practice of encoding and decoding data. Those transactions are often stored on computers distributed all over the world via a distributed ledger technology called blockchain (see below.)
Bitcoin can be divided into smaller units known as “satoshis” (up to 8 decimal places) and used for payments, but it’s also considered a store of value like gold. This is because the price of a single bitcoin has increased considerably since its inception – from less than a cent to tens of thousands of dollars. When discussed as a market asset, bitcoin is represented by the ticker symbol BTC.
The term “decentralized” is used often when discussing cryptocurrency, and simply means something that is widely distributed and has no single, centralized location or controlling authority. In the case of bitcoin, and indeed many other cryptocurrencies, the technology and infrastructure that govern the creation, supply, and security of it do not rely on centralized entities, like banks and governments, to manage it.
Instead, Bitcoin is designed in such a way that users can exchange value with one another directly through a peer-to-peer network; a type of network where all users have equal power and are connected directly to each other without a central server or intermediary company acting in the middle. This allows data to be shared and stored, or bitcoin payments to be sent and received seamlessly between parties.
The Bitcoin network (capital “B”, when referring to the network and technology, lower-case “b” when referring to the actual currency, bitcoin) is completely public, meaning anyone in the world with an internet connection and a device that can connect to it can participate without restriction. It’s also open-source, meaning anyone can view or share the source code Bitcoin was built upon.
Perhaps the easiest way to understand bitcoin is to think of it like the internet for money. The internet is purely digital, no single person owns or controls it, it’s borderless (meaning anyone with electricity and a device can connect to it), it runs 24/7, and people who use it can easily share data between one another. Now imagine if there was an ‘internet currency’ where everyone who used the internet could help to secure it, issue it and pay each other directly with it without having to involve a bank. That’s what bitcoin essentially is.
An alternative to fiat currency
Nakamoto originally designed bitcoin as an alternative to traditional money, with the goal for it to eventually become a globally accepted legal tender so people could use it to purchase goods and services.
However, bitcoin’s utility for payments has been stymied somewhat by its price volatility. Volatility is a word used to describe how much an asset’s price changes over a period of time. In the case of bitcoin, its price can change dramatically day to day – and even minute to minute – making it a less than ideal payment option. For example, you wouldn’t want to pay $3.50 for a cup of coffee and 5 minutes later it’s worth $4.30. Conversely, it doesn’t work out great for merchants either if bitcoin’s price falls dramatically after the coffee’s handed over.
In many ways, bitcoin works in the opposite way as traditional money: It is not controlled or issued by a central bank, it has a fixed supply (which means new bitcoins cannot be created at will) and it’s price is not predictable. Understanding these differences is the key to understanding bitcoin.
How does Bitcoin work?
It’s important to understand there are three separate components to Bitcoin, all of which combine together to create a decentralized payment system:
- The Bitcoin network
- The native cryptocurrency of the Bitcoin network, called bitcoin (BTC)
- The Bitcoin blockchain
Bitcoin runs on a peer-to-peer network where users — typically individuals or entities who want to exchange bitcoin with others on the network — do not require the help of intermediaries to execute and validate transactions. Users can choose to connect their computer directly to this network and download its public ledger in which all the historical bitcoin transactions are recorded.
This public ledger uses a technology known as “blockchain,” also referred to as “distributed ledger technology.” Blockchain technology is what allows cryptocurrency transactions to be verified, stored and ordered in an immutable, transparent way. Immutability and transparency are vitally important credentials for a payment system that relies on zero trust.
Whenever new transactions are confirmed and added to the ledger, the network updates every user’s copy of the ledger to reflect the latest changes. Think of it as an open Google document that updates automatically when anyone with access edits its content.
As its name implies, the Bitcoin blockchain is a digital string of chronologically ordered “blocks” — chunks of code that contain bitcoin transaction data. However, it is important to mention that validating transactions and bitcoin mining are separate processes. Mining can still occur whether transactions are added to the blockchain or not. Likewise, an explosion in Bitcoin transactions does not necessarily increase the rate at which miners find new blocks.
Irrespective of the volume of transactions waiting to be confirmed, the Bitcoin is programmed to allow new blocks to be added to the blockchain approximately once every 10 minutes.
Due to the public nature of the blockchain, all network participants can track and assess bitcoin transactions in real-time. This infrastructure reduces the possibility of an online payment issue known as double-spending. Double spending occurs when a user tries to spend the same cryptocurrency twice.
Bob, who has 1 bitcoin, might try to send it to both Rishi and Eliza at the same time and hope the system doesn’t spot it.
Double spending is prevented in the traditional banking system because reconciliation is performed by a central authority. It also isn’t a problem with physical cash because you can’t hand two people the same single dollar bill.
Bitcoin, however, has thousands of copies of the same ledger and so it requires the entire network of users to unanimously agree on the validity of each and every bitcoin transaction that takes place. This agreement between all parties is what’s known as “consensus.”
Just as banks constantly update the balances of their users, everyone that has a copy of the Bitcoin ledger is responsible for confirming and updating the balances of all bitcoin holders. So, the question is: How does the Bitcoin network ensure that consensus is achieved, even though there are countless copies of the public ledger stored all over the world? This is done through a process known as “proof-of-work.”
What is proof-of-work?
Computers in the Bitcoin network use a process called proof-of-work (PoW) to validate transactions and secure the network. Proof-of-work is the Bitcoin blockchain’s “consensus mechanism.”
While Proof-of-Work was the first and is generally the most common type of consensus mechanism for cryptocurrencies that run on blockchains, there are others — most notably proof-of-stake (PoS), which tends to consume less overall computing power (and therefore less energy).
Proof-of-work elevates certain network contributors to the role of “validators” – more commonly known as “miners” – only after they have proven their commitment to the network by dedicating an immense amount of computing power to discovering new blocks — a process that typically takes approximately 10 minutes.