How Does Bitcoin Work? Mining, Keys and Supply

Bitcoin works as digital cash on a public ledger: your wallet uses a secret key to sign a payment, a worldwide network of computers checks and records it, and a capped supply of 21 million coins means no one can print more. It was the first cryptocurrency, launched in 2009 by a pseudonymous creator known as Satoshi Nakamoto, and it remains the simplest to understand because it does one thing: move and store value without a central authority. This guide explains the moving parts — keys, transactions, mining and supply — without assuming any background.

Keys: what it means to own bitcoin

Owning bitcoin means controlling a private key. A bitcoin address is like a transparent glass safe that anyone can see into and drop money into, but only the holder of the matching private key can open. Your wallet is really just software that stores and uses those keys; the coins themselves never leave the blockchain. This is the origin of the phrase 'not your keys, not your coins': if someone else holds the key — an exchange, say — then they, not you, ultimately control the bitcoin. Lose your key with no backup and the coins are frozen forever, because there is no company that can reset it. That single fact explains most of Bitcoin's power and most of its danger.

How a payment gets confirmed

When you send bitcoin, your wallet signs the transaction with your private key and broadcasts it to the network. Computers around the world check that the signature is valid and that those coins have not already been spent, then place the transaction in a queue. Roughly every ten minutes, the network bundles queued transactions into a new block and adds it to the chain; your payment is 'confirmed' once it is in a block, and more secure with each additional block placed on top. This is why a merchant might wait for a few confirmations before treating a large payment as final. The underlying record-keeping is the same for every cryptocurrency, and we cover it in how a blockchain works.

What mining actually does

Mining is often misunderstood as 'solving maths to find coins,' but its real job is security. Miners are computers competing to be the one that adds the next block, and to win they must spend real electricity solving a deliberately hard puzzle. The winner earns newly created bitcoin plus the transaction fees in that block, which is how new coins enter circulation and how miners are paid for their work. The genius is economic: because adding blocks costs so much energy, rewriting the history would cost more than any attacker could gain, so honesty is the profitable strategy. The flip side is that all this computation uses a large amount of energy, a real and fair criticism of Bitcoin's design that its proof-of-work model accepts as the price of security.

Where new bitcoin comes from — and why it stops

Bitcoin's supply is capped at 21 million coins, and the schedule for releasing them is fixed in the software. New coins are paid to miners as a block reward, but that reward is cut in half roughly every four years, an event called the halving. The most recent halving, in April 2024, reduced the reward from 6.25 to 3.125 bitcoin per block. Because of this steadily shrinking issuance, the last new bitcoin is expected to be mined around the year 2140, after which miners will be paid only from transaction fees. This hard-coded scarcity is central to Bitcoin's identity as 'digital gold,' though it is worth remembering that scarcity alone does not make something valuable or a good investment — plenty of scarce things are worth nothing.

What Bitcoin is good at, and what it is not

Bitcoin is deliberately simple and conservative. It is designed to be a secure, censorship-resistant store and transfer of value, and it does that job well; it is intentionally not a platform for complex applications, which is the niche Ethereum and smart contracts fill instead. As everyday spending money Bitcoin is awkward: confirmations take minutes, fees vary, and its price can swing wildly from week to week. None of this tells you whether to own any — that is a decision only you can make, with money you can afford to lose. The goal here is only that you understand what it is before you ever consider it, and remember that nothing on this page is financial advice.

Is Bitcoin anonymous?

Not really — Bitcoin is better described as pseudonymous. Every transaction is public and permanently visible on the blockchain, tied to addresses rather than names. Your name is not written into the ledger, but addresses can often be linked to real identities, especially once you buy or sell through a regulated exchange that verifies who you are. Analysis firms and law enforcement routinely trace flows of bitcoin across the public record. So while Bitcoin offers some privacy compared with a bank account, it is a mistake to think of it as untraceable or a tool for hiding money; the transparency that secures the network also exposes its activity to anyone who cares to look.

Why the price moves so much

Bitcoin's price is famously volatile because it is driven almost entirely by supply and demand for a fixed-supply asset with no cash flows or central bank to steady it. Unlike a company share, bitcoin produces no earnings and pays no dividend, so there is no agreed way to value it; its price is simply whatever people are willing to pay at a given moment, which shifts with sentiment, news, regulation and waves of speculation. That is why it has repeatedly risen and fallen by large amounts in short periods — reaching an all-time high near $126,000 in October 2025 and trading roughly a third below that by September 2026 (checked September 2026). Understanding this helps explain why owning bitcoin is high-risk and why no one can reliably predict where it goes next. It is not a reason to buy or avoid it, only to understand what you would be holding.