Bitcoin Explained: What It Is and How It Actually Works

Before exploring what Bitcoin is, it helps to ask a simpler question: what is money? Every modern society uses some kind of money to exchange goods and services, and at its core, money represents value. If I do some work or sell something, I receive money that represents what that work or item is worth. Over the centuries, money has taken remarkably different forms: clay tablets, shells, livestock, giant stone wheels, metal coins, paper notes and, more recently, electronic entries in bank databases. That last one matters. Most of the money you use today is not a pile of notes sitting somewhere. When you transfer $100 with your banking app, what really changes is the bank’s electronic record of who has what. Bitcoin takes that idea and removes the bank from the middle, using a public network of computers to keep a shared record of transactions instead, with no central bank issuing it and no single company owning the network.

What is Bitcoin?

Bitcoin is a digital asset and payment network designed to let people transfer value directly to one another without relying on a central authority. The idea was set out in a paper called Bitcoin: A Peer-to-Peer Electronic Cash System, published on 31 October 2008 under the name Satoshi Nakamoto, and the network went live in January 2009, as crypto company Banxa explains. Satoshi’s real identity is still unknown. But the more interesting question is the problem Bitcoin was built to solve.

If I hand you a $20 note, I no longer have it. Digital information is different: if I send you a photo or an email, I still have the original. Money cannot work that way, because if a digital coin could be copied and spent twice, it would soon be worthless. This is called the double-spending problem. Banks solve it for ordinary digital money by keeping a central ledger; when you pay by card, your bank checks you have the funds, approves the payment and updates the balances, acting as the trusted middleman. Bitcoin solves it differently, with a shared public ledger called the blockchain.

How the blockchain works

The blockchain is a chronological record of every Bitcoin transaction. Transactions are collected into blocks, and each block is cryptographically linked to the one before it, forming a chain that stretches back to the very first block, known as the genesis block. Computers across the network independently check that every transaction follows Bitcoin’s rules. That does not make cheating impossible, but changing an established transaction would mean overcoming the network’s cryptography and its agreed rules rather than simply persuading one bank to edit its database. That is the central idea: the network lets people agree on who owns what without having to trust any single organisation.

The easiest way to see it in action is to follow a payment. Say Alice wants to send some Bitcoin to Bob. She creates a transaction in her wallet and signs it with her private key, which proves mathematically that she controls the Bitcoin being spent. The transaction is broadcast to the network, where miners compete to include it in the next block. Once that block is accepted, the payment is part of the blockchain and has its first confirmation, with each new block adding another.

Your wallet does not actually contain Bitcoin

The word “wallet” is misleading. A Bitcoin wallet does not hold coins, or even a file containing them. The blockchain records which Bitcoin belongs to which addresses; your wallet manages the cryptographic keys that let you authorise payments from those addresses. The most important is your private key. If someone gets hold of it, they may be able to spend your Bitcoin, and if you lose access to your keys or recovery details, there may be no bank or company that can reset your password and restore your funds. That is one of Bitcoin’s defining features, and one of its biggest practical risks.

What mining actually is

Bitcoin mining does not involve digging for anything. It is a competition in which specialised computers perform enormous numbers of calculations to solve a deliberately difficult puzzle, called proof of work. The first miner to find a valid solution adds the next block of transactions to the blockchain and receives newly created Bitcoin, called the block subsidy, plus the transaction fees in that block. Mining does three jobs at once: it processes transactions, it releases new Bitcoin into circulation, and it makes rewriting the transaction history extremely expensive. It is also highly competitive and needs specialised hardware and a lot of electricity, so it is not a matter of running some software on a home computer to generate free Bitcoin.

Why there will only ever be 21 million

Bitcoin was designed with a maximum supply of 21 million coins. The reward for mining a block is cut in half roughly every 210,000 blocks, or about every four years, in an event called the halving. According to Blockstream, the reward started at 50 Bitcoin per block in 2009, and the most recent halving, in April 2024, cut it from 6.25 to 3.125. The next is expected around 2028, depending on how quickly blocks are produced, and new issuance should reach zero around the year 2140. Importantly, the cap is not just a promise; the network’s rules reject any block that breaks the supply limit. That fixed supply is why Bitcoin is often compared with gold, although whether scarcity gives it lasting value is a separate question. A single Bitcoin can also be divided into 100 million smaller units called satoshis, or sats, so small payments are still possible however high the price of a whole coin climbs.

What to know before buying any

Understanding how Bitcoin works is one thing; deciding whether to buy it is another. Bitcoin is a high-risk asset. Its price can move dramatically in a short time, there is no guaranteed return, and big rises in the past say nothing about what it will do next. Unlike a share in a company, it produces no profits that can be used to value it, so its price is simply whatever buyers and sellers agree, driven by demand, speculation, sentiment, regulation and wider financial conditions. It has suffered several large falls in its history, and investors can lose a lot of money, which is exactly why I have not put a price in this article; any figure would be out of date almost immediately.

The blockchain can also be secure while your Bitcoin is not. The network’s cryptography protects transactions, but an exchange account, a phone, a computer, a wallet or a private key can still be compromised. Crypto scams are common, from fake trading platforms and phishing sites to impersonation and promises of guaranteed returns. If someone contacts you out of the blue promising guaranteed profits from Bitcoin, treat it as a warning sign, not an opportunity. Bitcoin is not anonymous either. Every transaction is publicly recorded on the blockchain against addresses rather than names, which makes it pseudonymous; if an address can be linked to a real person, the transactions tied to it can potentially be traced, which is very different from paying in cash.

For Australian readers, one of the most important points is that Bitcoin is not a bank deposit. The Australian Government’s Financial Claims Scheme protects eligible deposits with banks, building societies and credit unions up to $250,000 per account holder per institution, but Bitcoin is not an eligible deposit, so it has none of that protection. And the protections that come with a regulated financial service do not automatically apply to every crypto platform or product. ASIC’s Moneysmart website explains these risks in detail, and it is the best place to start before buying.

The rules in Australia are changing

Buying and holding Bitcoin is legal in Australia, but the rules for businesses offering crypto services are tightening. AUSTRAC regulates crypto businesses under Australia’s anti-money-laundering laws. In 2026 it renamed digital currency exchanges “virtual asset service providers”, widened the range of crypto services that must register, and began publishing a public register of them, as a Dwyer Harris legal update reports. Then, on 9 April 2027, a new licensing regime for crypto platforms begins, under the Corporations Amendment (Digital Assets Framework) Act 2026, which passed Parliament on 1 April 2026, according to ASIC. It gives ASIC a much bigger role in licensing and supervising crypto platforms. Because these rules keep changing, check ASIC’s and AUSTRAC’s current guidance rather than relying on an old article or a social media post.

Bitcoin can create a tax bill even if you never cash out

The Australian Taxation Office generally treats crypto as an asset rather than money, so selling Bitcoin is usually a capital gains tax event. But selling it for Australian dollars is not the only trigger. Swapping it for another crypto, gifting it or spending it on a purchase can also count as a disposal, which means you could owe tax without ever moving money back into your bank account. There are limited exceptions, such as some personal-use assets, so it depends on what you do with it. Keep good records of every purchase, sale, transfer and fee, along with the Australian-dollar value at the time, and if the amounts become significant, talk to a qualified tax professional.

So, is Bitcoin money?

That depends on what you mean by money. Bitcoin was designed as peer-to-peer electronic cash, and it can be used to send value between people. But it is not legal tender in Australia, and it is not widely used for everyday purchases here. In practice, it behaves much more like a high-risk asset than a replacement for your savings account. It can work as a payment network and a digital asset without becoming the money you use to buy groceries, pay the mortgage or receive your salary.

Why Bitcoin still matters

Whatever you think about its price, Bitcoin introduced a genuinely clever idea: a shared financial ledger with nobody in charge of it. The combination of cryptography, digital signatures, proof of work, network-wide agreement and a fixed issuance schedule has kept it running since 2009 and inspired an entire industry of cryptocurrencies and blockchain projects. Whether it becomes widely used money, stays mainly a speculative asset or turns into something else is still an open question. The core idea, though, is simple: transferring digital value without a bank keeping the master record. And that is exactly why it is worth understanding what you are buying before you buy any. If you are curious about the people and ideas behind other technology we use every day, my posts on why Bluetooth is called Bluetooth and the inventor of the internet’s regret about the URL are good places to start.

This article is general information only and is not financial advice. Bitcoin and other crypto assets are high-risk and can lose substantial value. Australian tax and financial-services rules can change, so check current guidance from the ATO, ASIC and AUSTRAC, and consider getting advice from an appropriately qualified professional before making financial decisions.

Sources

• Banxa: What is the Bitcoin halving?
• Blockstream: What is the Bitcoin halving?
• ASIC: Final call for firms to act before ASIC’s digital asset licensing deadline
• Dwyer Harris: Financial services and credit monthly update, April 2026
• Gilbert + Tobin: ASIC publishes implementation roadmap for digital asset regulation
• Australian Taxation Office: Crypto asset investments and tax
• ASIC’s Moneysmart