Bitcoin is the world's first successful decentralized cryptocurrency and payment system, launched in 2009 by a mysterious creator known as Satoshi Nakamoto. The term "cryptocurrency" refers to a group of digital assets whose transactions are secured and verified through cryptography—a scientific practice of encoding and decoding data. These transactions are usually stored on computers distributed worldwide using a distributed ledger technology called blockchain.
Bitcoin can be divided into smaller units, known as "satoshis" (up to 8 decimal places), and is used for payments. It is also considered a store of value like gold, as the price of a single Bitcoin has risen significantly since its inception—from less than a penny to tens of thousands of dollars. As a market asset, Bitcoin is represented by the symbol BTC.
Understanding Decentralization
The term "decentralized" is often used when discussing cryptocurrencies and simply means something widely distributed without a single location or central controlling authority. In the case of Bitcoin and many other cryptocurrencies, the technology and infrastructure governing their creation, supply, and security do not rely on central entities like banks or governments for management.
Instead, Bitcoin is designed so that users can exchange value directly with each other through a peer-to-peer network—a type of network where all users have equal power and are directly connected without a central server or intermediary company. This allows data to be shared and stored, or payments in Bitcoin to be sent and received seamlessly between parties.
The Bitcoin network (with a capital "B" when referring to the network and technology, and a lowercase "b" for the currency, bitcoin) is completely public. This means anyone in the world with an internet connection and a device can participate without restrictions. It is also open-source, meaning anyone can view or share the source code upon which Bitcoin was built.
Perhaps the simplest way to understand Bitcoin is to think of it as the internet of money. The internet is purely digital, no one owns or controls it, it has no borders, it operates 24/7, and its users can easily share data. Now imagine if there were an "internet currency" where all users could help protect it, issue it, and pay each other directly without needing a bank. That is essentially Bitcoin.
Bitcoin as an Alternative to Fiat Currency
Nakamoto originally designed Bitcoin as an alternative to traditional money, with the goal of it eventually becoming a globally accepted legal tender for purchasing goods and services.
However, Bitcoin's utility for payments has been somewhat limited by its price volatility. Volatility describes how much an asset's price varies over time. In Bitcoin's case, its price can change drastically daily, or even minute by minute, making it a less-than-ideal payment option. For example, you wouldn't want to pay $3.50 for a coffee only to find it costs $4.30 five minutes later. Conversely, it's beneficial for merchants if Bitcoin's price doesn’t drop drastically after delivering the coffee.
In many ways, Bitcoin operates opposite to traditional money: it is not controlled or issued by a central bank, it has a fixed supply (meaning new bitcoins cannot be created at will), and its price is unpredictable. Understanding these differences is key to understanding Bitcoin.
How Bitcoin Works
It's important to understand that Bitcoin has three separate components that combine to create a decentralized payment system:
- The Bitcoin network
- The native cryptocurrency of the Bitcoin network, called bitcoin
- The Bitcoin blockchain
Bitcoin operates on a peer-to-peer network where users—typically individuals or entities wanting to exchange bitcoin with others on the network—do not need intermediaries to execute and validate transactions. Users can connect their computers directly to this network and download its public ledger, where all historical Bitcoin transactions are recorded.
This public ledger uses a technology known as "blockchain," also referred to as "distributed ledger technology." Blockchain technology allows cryptocurrency transactions to be verified, stored, and ordered in an immutable and transparent manner. Immutability and transparency are vital credentials for a trustless payment system.
Whenever new transactions are confirmed and added to the ledger, the network updates each user's copy to reflect the latest changes. It's like an open Google document that automatically updates when anyone with access edits its content.
As the name suggests, the Bitcoin blockchain is a digital chain of "blocks" arranged chronologically—chunks of code containing Bitcoin transaction data. However, it's important to note that transaction validation and Bitcoin mining are separate processes. Mining can continue regardless of whether transactions are added to the blockchain. Similarly, a sudden increase in Bitcoin transactions does not necessarily increase the rate at which miners discover new blocks.
Regardless of the volume of transactions awaiting confirmation, Bitcoin is programmed to allow new blocks to be added to the blockchain approximately every 10 minutes.
Thanks to the public nature of the blockchain, all network participants can track and evaluate Bitcoin transactions in real-time. This infrastructure reduces the possibility of an online payment problem known as double-spending. Double-spending occurs when a user attempts to spend the same cryptocurrency twice.
In the traditional banking system, double-spending is avoided because reconciliation is handled by a central authority. It also isn't a problem with physical cash, as the same dollar bill cannot be handed to two people.
A purely peer-to-peer version of electronic cash would allow online payments to be sent directly between parties without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending.
However, Bitcoin has thousands of copies of the same ledger, so it requires the entire network of users to unanimously agree on the validity of each Bitcoin transaction made. This agreement among all parties is known as "consensus."
Just as banks constantly update their users' balances, everyone with 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 consensus, despite the existence of countless copies of the public ledger stored worldwide? This is achieved through a process known as "proof of work."
What Is Proof of Work?
Computers on the Bitcoin network use a process called proof of work (PoW) to validate transactions and secure the network. Proof of work is the consensus mechanism of the Bitcoin blockchain.
While Proof of Work was the first and is generally the most common type of consensus mechanism for cryptocurrencies running on blockchains, there are others—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 demonstrated their commitment to the network by dedic immense computational power to discovering new blocks—a process that generally takes about 10 minutes.
When a new block is discovered, the miner who found it during the mining process can fill it with 1 megabyte of validated transactions. This new block is added to the chain, and each miner's copy of the ledger is updated to reflect the new data. In return for their effort, the miner can keep the fees associated with the transactions they add, in addition to receiving a amount of newly minted bitcoin. The new bitcoin created and delivered to successful miners is known as the "block reward."
All Bitcoin users must pay a network fee each time they send a transaction (usually based on its size) before the payment can be validated. It's like buying a stamp to mail a letter.
The goal when adding a transaction fee is to match or exceed the average fee paid by other network participants so that the transaction is processed promptly. Miners must cover their own electricity and maintenance costs while operating their machines all day to validate the Bitcoin network, so they prioritize transactions with the highest fees to maximize profitability when completing new blocks.
You can view average fees in the Bitcoin mempool, which can be compared to a waiting room where unconfirmed transactions are held until miners select and add them to the blockchain.
How Is Bitcoin Created?
The Bitcoin network automatically releases newly minted bitcoin to miners when they discover and add new blocks to the blockchain. The total supply of Bitcoin is capped at 21 million coins, meaning that once the number of coins in circulation reaches 21 million, the protocol will stop minting new coins. In a way, Bitcoin mining serves both as a transaction validation process and a bitcoin issuance process (until all coins are mined, it will only function as a transaction validation process).
Importantly, increasing the processing power dedicated to Bitcoin mining does not mean that more bitcoin is mined. Miners with greater processing power only increase their chances of being rewarded with the next block, so the amount of bitcoin mined remains relatively stable over time.
The Bitcoin network uses a coin distribution strategy known as "Bitcoin halving." This ensures that the amount of bitcoin distributed to miners decreases over time. By gradually reducing the supply of new bitcoin entering circulation, the idea is to help sustain the asset's price (based on the fundamental principles of supply and demand).
A Bitcoin halving (sometimes called "halvenings") occurs every 210,000 blocks, or approximately every four years. When the Bitcoin protocol was first launched in 2009, each successful miner received 50 bitcoin as a block reward. In 2021, block rewards were 6.25 BTC after a reduction from 12.5 BTC before the Bitcoin halving in May 2020.
In April 2024, Bitcoin experienced its fourth halving, reducing the block reward from 6.25 BTC to 3.125 BTC. This event, coded into Bitcoin's software, occurs roughly every four years and reduces the rate of new bitcoin creation. It is one of the core features designed to preserve Bitcoin's scarcity.
By early 2025, over 19.7 million BTC were in circulation, leaving just over 1.2 million to be mined in the next 100 years. However, considering the halving principle and other network factors like mining difficulty, it is estimated that the last bitcoin will be mined around the year 2140.
As computers become faster and the proof-of-work calculation applied to bitcoin creation increases, the difficulty rises proportionally to keep new production constant. Therefore, it is known in advance how many new bitcoin will be created each year in the future.
How to Mine Bitcoin
Bitcoin mining is a process that adds transactions to the blockchain and creates new bitcoin. It involves solving complex mathematical problems using powerful, specialized computer hardware. There was a time in history when it was reasonable to mine Bitcoin from your own home, but as computational hardware requirements have increased, most people entering the space generally join a mining pool—a group of miners who pool resources for greater efficiency.
Miners use hardware, often application-specific integrated circuits (ASICs), to solve these problems. This process is competitive: the first to solve the problem adds the next block to the blockchain and receives a Bitcoin reward.
Bitcoin mining is not easy. It consumes a lot of energy, leading to high electricity costs and considerable heat generation, so cooling solutions are essential for mining hardware. Additionally, it involves a significant initial investment in equipment, and profitability is not guaranteed due to Bitcoin's price volatility and increasing mining difficulty. Finally, regulatory scrutiny or bans in certain regions due to environmental or other concerns can present challenges, so always consult local laws before starting. Despite the risks, Bitcoin mining can be potentially profitable for those with the right setup and an understanding of the risks.
What Is a Bitcoin Wallet?
A Bitcoin wallet is a program that runs on a computer or dedicated device and provides the functionality needed to secure, send, and receive bitcoin. Contrary to what one might think, the bitcoin itself is not stored in a wallet. Instead, the wallet protects the cryptographic keys—essentially, a type of highly specialized password—that certify ownership of a specific amount of bitcoin on the Bitcoin network.
Whenever a Bitcoin transaction is executed, ownership of the bitcoin is transferred from the sender to the recipient, and the network designates the recipient's keys as the new "password" to access the bitcoin.
Bitcoin uses a system called public-key cryptography (PKC) to preserve the integrity of its blockchain. Originally used to encrypt and decrypt messages, PKC is now commonly used in blockchains to secure transactions. This system allows only individuals with the correct set of keys to access specific coins.
Two types of keys are required to own and execute Bitcoin transactions: a private key and a public key. Both are randomly generated strings of alphanumeric characters used to encrypt and decrypt transactions. On the Bitcoin network, PKC implements one-way mathematical functions that are easy to solve in one direction and virtually impossible to reverse.
The blockchain uses a one-way mathematical algorithm to create a public key from the private key. With this, it is virtually impossible to regenerate the private key from the public key, meaning it's best not to lose the keys (or forget your password to access them). Additionally, you will receive a public address, which is simply the hashed or shortened form of your public key.
This address functions similarly to a home address and is shared to receive bitcoin. On the other hand, the private key must be kept hidden, just as your debit card PIN is for your eyes only.
To execute transactions, you must use your private key and public key to encrypt and sign your Bitcoin transactions. Additionally, you must include the recipient's public address. This way, only the recipient with the correct private key will be able to unlock or claim the transferred bitcoin.
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Frequently Asked Questions
What is the main purpose of Bitcoin?
Bitcoin was designed as a decentralized digital currency to enable peer-to-peer transactions without intermediaries like banks. It aims to provide an alternative to traditional fiat currencies by offering a transparent, secure, and borderless payment system.
How does Bitcoin mining work?
Bitcoin mining involves using specialized hardware to solve complex mathematical problems. Miners compete to validate transactions and add new blocks to the blockchain. Successful miners are rewarded with newly created bitcoin and transaction fees, which helps secure the network and process transactions.
What happens during a Bitcoin halving?
A Bitcoin halving is an event that reduces the block reward given to miners by 50%. It occurs approximately every four years or after every 210,000 blocks. This mechanism controls the supply of new bitcoin, making it scarcer over time and potentially influencing its price.
Can Bitcoin be used for everyday purchases?
While Bitcoin can be used for purchases, its price volatility makes it less practical for everyday transactions compared to stable currencies. However, some merchants and online platforms accept Bitcoin, and solutions like payment processors are improving its usability for daily use.
How do I store Bitcoin securely?
Bitcoin is stored in digital wallets that secure your private keys. For optimal security, use hardware wallets or reputable software wallets, enable two-factor authentication, and never share your private keys. Regularly updating your software and backing up your keys are also essential steps.
Is Bitcoin legal?
Bitcoin's legality varies by country. Many nations recognize it as a legal asset or currency, while others have restrictions or bans. Always check local regulations regarding cryptocurrency use, trading, and mining to ensure compliance with the law.