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The simple Bitcoin guide

Disclaimer: This guide is written for education and general understanding only. It is not financial advice, investment advice, legal advice or tax advice. Bitcoin is risky and can fall sharply in value. Rules, taxes and market practice can change. Use qualified professional advice for investing, taxes, business use, large amounts or legal questions. You are responsible for your own decisions.

Last updated: April 2026

1. What is Bitcoin?

Bitcoin is an open digital money system. It makes it possible to send and receive value over the internet without a bank, card network, payment app or other central actor having to approve the transaction.

The system consists of a global network of computers that follow the same rules. Those rules are open, verifiable and based on cryptography, digital signatures and a shared transaction history called the blockchain.

The currency inside the network is called bitcoin. It is usually abbreviated BTC. One bitcoin can be divided into 100,000,000 smaller units. The smallest unit is called a satoshi, or sat.

Bitcoin in one sentence: Bitcoin is an open protocol for digital money where ownership is proven with private keys and transactions are verified by a global network instead of a central bank.

Bitcoin is not a company

Bitcoin has no headquarters, no customer support department, no CEO and no central server that controls the system. It is closer to an internet protocol than to an app.

Email is not owned by Gmail, even though many people use Gmail for email. In the same way, Bitcoin is not owned by an exchange, even though many people buy bitcoin through exchanges.

This distinction matters. An exchange can freeze accounts, require identification, charge fees or go bankrupt. The Bitcoin network is something else: an open protocol maintained through the interaction of users, nodes, developers and miners.

Bitcoin, bitcoin, BTC and sats

·         Bitcoin with a capital B means the network, the protocol and the technology.

·         bitcoin with a lowercase b means the asset or currency used inside the network.

·         BTC is the most common abbreviation for bitcoin.

·         satoshi or sats means the smallest unit in Bitcoin. One satoshi is 0.00000001 BTC.

This may sound like a small language detail, but it helps. Bitcoin is the network. bitcoin is what moves inside the network.

What Bitcoin solves

The most important problem Bitcoin solved is called double spending. Double spending means trying to use the same digital money more than once.

Digital information is normally easy to copy. A picture, text file or document can be sent to thousands of people without the original disappearing. Money cannot work that way. If the same digital coin can be copied and spent several times, the system breaks.

Bitcoin solves this without a central controller. Valid transactions are ordered into one shared history, and the network accepts only the history that follows the rules and has the most proven work behind it.

Simple version: Bitcoin makes digital money scarce. A file can be copied. A bitcoin cannot be copied in the same way, because the network accepts only one valid spending history.

2. Three simple ways to understand Bitcoin

Bitcoin can be described in several ways. No analogy is perfect, but three mental models are especially useful: digital cash, digital gold and an internet protocol for money.

Bitcoin as digital cash

With physical cash, you can pay another person directly. You do not need a card network, bank opening hours or a payment app as an intermediary.

Bitcoin works in a similar way, but digitally. You can send value directly to another person. The difference is that the transaction happens over the internet and ownership is controlled by private keys.

The analogy has limits. Cash is physical and more naturally private in everyday use. Bitcoin transactions are public on the blockchain, even if addresses do not automatically contain names.

Bitcoin as digital gold

Gold has historically been valuable partly because it is scarce, durable and difficult to produce. Bitcoin attempts to create a digital form of scarcity.

Under the current consensus rules, no more than about 21 million bitcoin will ever exist. New bitcoin are created through mining, and the issuance rate is cut in half roughly every four years.

The gold analogy is about scarcity, verifiability and the difficulty of creating more supply. It does not mean that bitcoin must behave like gold in price or risk.

Bitcoin as an internet protocol for money

The internet made information global, fast and cheap to move. Bitcoin tries to do something similar for value.

Just as the internet is not a single website, Bitcoin is not a single app. It is an open protocol that others can build on: wallets, payment services, exchanges, analysis tools and new layers such as Lightning.

The key difference from ordinary digital payments

When you pay with a card, PayPal, a bank transfer or a mobile payment app, databases controlled by companies and banks are updated. The payment is digital, but the system is centralized. Someone controls accounts, identities, rules, opening hours and disputes.

When you use Bitcoin, your wallet creates a transaction, signs it and broadcasts it to a global network. The network checks whether the transaction follows the rules. If it does, it can be included in a block and become part of the shared history.

The most accurate mental model: Bitcoin is an open system for owning and moving digital value without a central counterparty.

3. Why Bitcoin was created

Bitcoin was published in 2008, during a global financial crisis. The idea was to create a system where two parties could send digital payments directly to each other without relying on a financial institution.

That does not mean Bitcoin is only a protest against banks. The technical innovation is broader than that. Bitcoin shows that a global network can agree on a shared transaction history without a central administrator.

The problem before Bitcoin

Before Bitcoin, digital money almost always required a central party. That party could be a bank, a card network, a payment platform or a server that kept track of who owned what.

This can work well, but it requires trust. You must trust the central party not to make mistakes, not to censor you, not to lose data, not to go bankrupt and not to change the rules in a way that harms you.

Bitcoin replaces the central party with open rules, cryptography, proof of work and economic incentives.

The genesis block

The first block in the Bitcoin blockchain was created on 3 January 2009. It is called the genesis block.

Inside that block is the text “Chancellor on brink of second bailout for banks”, taken from a newspaper headline on the same day.

The message is usually understood in two ways. It acts as a timestamp showing that the block could not have been created before the headline was published. It also marks the historical environment in which Bitcoin was born: distrust of a system where banks could take large risks and then be rescued by the state.

Bitcoin is voluntary

Bitcoin forces nobody to use it. The point is that the system exists as an alternative.

For some people, bitcoin is a way to make global payments. For others, it is a way to save in an asset with a predictable supply. For others, it is a technical experiment in decentralized systems. All three perspectives can coexist.

4. What makes bitcoin money?

Money is not just coins and banknotes. Money is a social and technical tool that makes trade easier.

Instead of trading fish for shoes, shoes for firewood and firewood for flour, people use a shared medium of exchange. This allows trade to happen faster, over longer distances and between people who do not know each other.

The three functions of money

Money is usually described through three classic functions.

Medium of exchange: Something that can be used to pay. Bitcoin can be used for payments, but taxes, volatility and transaction fees can make it impractical for everyday spending in some countries.

Unit of account: Something prices can be measured in. Most prices are still quoted in dollars, euros, pounds or local currencies. Bitcoin is often used as a secondary unit of account, for example BTC or sats.

Store of value: Something that can preserve purchasing power over time. Bitcoin has a limited supply, but its price is volatile. That makes its role as a store of value possible, but uncertain, especially over short periods.

Why scarcity matters

Something that is supposed to store value needs to be difficult to create in unlimited amounts. If supply can increase without limit, it becomes harder to preserve value.

Gold has historically worked as a store of value partly because it is scarce and costly to mine. Bitcoin issuance is not controlled by geology, mining companies or central banks. It is controlled by the rules of the protocol.

Every full node can check that no block creates more bitcoin than the rules allow.

Fiat money and bitcoin

Dollars, euros, pounds and most national currencies are fiat money. They have value because society accepts them, governments require taxes in them and the banking system uses them as units of account. They are not redeemable for gold at a fixed rate.

Fiat money has clear advantages. It is more stable in daily life, widely accepted inside its country or region and supported by legal systems.

Fiat money also has drawbacks. The supply can increase through monetary policy, bank accounts can be restricted and international payments can be slow, expensive or dependent on several intermediaries.

Bitcoin has opposite properties on several points. The supply is predictable, the system is global and no central party can change the rules alone. At the same time, the price is volatile, the user carries more responsibility and on-chain transactions are not always practical for everyday purchases.

Useful rule of thumb: Fiat money relies heavily on institutional trust. Bitcoin relies more heavily on verifiable rules. One does not automatically replace the other, but they solve different problems.

5. How Bitcoin works from keys to blocks

For a user, Bitcoin can look simple: open a wallet, enter the recipient address, choose an amount and send.

Under the surface, more is happening.

A Bitcoin payment step by step

1.    Your wallet uses a private key. The private key gives control over bitcoin that can be spent.

2.    The wallet creates a transaction. The transaction says which previously received bitcoin will be spent and where the value should go.

3.    The transaction is digitally signed. The signature proves that you have the right to spend without revealing the private key.

4.    The transaction is broadcast to the Bitcoin network.

5.    Nodes check that the transaction follows the rules.

6.    If the transaction is valid, it enters the mempool, a waiting area for unconfirmed transactions.

7.    Miners choose transactions from the mempool and try to create the next block.

8.    When a valid block is found, it is broadcast across the network.

9.    Nodes check the block and build on top of it if it follows the rules.

10.  The transaction now has its first confirmation. Every new block on top gives it another confirmation.

An account balance is a simplification

A bank shows a balance on an account. Bitcoin does not work in exactly the same way.

Bitcoin uses a model based on unspent transaction outputs, often called UTXOs. A wallet adds together the previously received amounts that are still available to spend.

A simple analogy is paper money. If you have three 100-dollar bills, you have 300 dollars, but the money still consists of three separate bills. In Bitcoin, the wallet can show a total balance, but underneath that balance are several separate unspent pieces.

Change addresses

When you pay with a banknote, you often receive change. Bitcoin works in a similar way.

If you spend a UTXO that is larger than the amount you want to send, the rest is sent back to a new address controlled by your wallet. This is often called a change address.

This is one reason why a wallet can contain many addresses. It is also why you should not try to judge someone’s total holdings by looking at one address.

6. The blockchain: Bitcoin’s shared history

The blockchain is Bitcoin’s public transaction history. It is not an ordinary database run by a company. It is a chain of blocks validated and stored by many independent nodes.

What is a block?

A block is a bundle of transactions plus metadata. The metadata includes, among other things, a reference to the previous block.

That reference is created with a hash, a digital fingerprint of data. If someone changes data in an old block, the hash of that block changes. Then the reference inside the next block no longer matches.

To cheat, an attacker would therefore not only need to change an old block. The attacker would also need to redo the work for every later block and catch up with the chain that the rest of the network is building on.

The book page analogy

Imagine a book where every page ends with two fingerprints: one fingerprint of the page content and one fingerprint of the previous page.

If someone changes a line on page 20, that page’s fingerprint changes. Then page 21 becomes wrong, because it points to the old fingerprint. Then page 22 becomes wrong, and so on.

A blockchain works in a similar way, but with cryptographic fingerprints and a global network that checks the rules.

Blockchain is not magic

The word blockchain is sometimes used as if it automatically makes a system secure, modern or decentralized. That is not true.

A blockchain is only a data structure unless it is combined with a working consensus mechanism, economic incentives and nodes that actually verify the rules.

Bitcoin’s blockchain is interesting because it is connected to proof of work, global distribution, open verification and an economic asset used to reward miners.

7. Mining, proof of work and difficulty

Mining is the process through which new blocks are created. Miners collect transactions, build a candidate block and try to find a hash value that satisfies the network’s requirement.

Finding a valid block requires a large amount of computation. Checking the result is easy for other nodes.

Why proof of work is needed

Proof of work makes blocks expensive to create but cheap to verify.

This matters because the Bitcoin network is open. Anyone is allowed to try to create a block, but nobody is allowed to create a block that breaks the rules.

The work acts as an economic defense. To rewrite history, an attacker would need to control enormous computing power and pay the associated energy cost, while the rest of the network continues building on the valid chain.

Block subsidy and transaction fees

When a miner finds a valid block, the miner may create a special transaction. It contains the block subsidy, meaning newly issued bitcoin, plus transaction fees from the transactions included in the block.

The block subsidy started at 50 BTC per block. It is cut in half every 210,000 blocks, roughly every four years. After the 2024 halving, the subsidy is 3.125 BTC per block.

Over the long term, the block subsidy trends toward zero. The idea is that miners will increasingly be paid by transaction fees.

Difficulty

Bitcoin tries to keep the average block time around 10 minutes.

If more computing power joins the network, blocks are found faster. The difficulty then adjusts upward. If computing power leaves the network, the difficulty adjusts downward.

The adjustment happens every 2,016 blocks, roughly every two weeks.

Mining is not the same as controlling Bitcoin

Miners propose blocks. Full nodes verify blocks.

A miner can try to create a block with too many bitcoin or invalid transactions, but full nodes should reject that block. For that reason, it is misleading to say that miners alone control Bitcoin.

8. Nodes, rules and consensus

A full node is a computer running Bitcoin software that independently checks blocks and transactions. A full node does not need to trust an exchange, a block explorer or another server to know whether a transaction follows the rules.

Who controls Bitcoin?

Nobody owns the Bitcoin network.

Developers can propose and write code, but they cannot force users to run it. Miners can create blocks, but their blocks are accepted only if nodes judge them valid. Users and businesses can choose which software and which rules they accept.

Bitcoin therefore works through consensus around rules, not through a central boss.

Consensus is not democracy

Bitcoin is often called democratic, but that is not quite accurate.

Bitcoin does not have one person, one vote. It is more like a voluntary rule system. If you want to remain in the same network, your node must follow the same basic rules that the rest of the network accepts.

Forks: when chains or rules split

The word fork is used in several ways.

A temporary chain fork can happen when two miners find valid blocks at almost the same height at almost the same time. The network normally resolves this when the next block is found on top of one branch. The other branch is then abandoned.

A rule change can also be called a fork. A soft fork makes the rules stricter in a way older nodes can still accept. A hard fork changes the rules in a way that is not backward compatible. If users disagree, the result can be two separate networks.

9. Transactions, fees and confirmations

A Bitcoin transaction is not final at the exact moment it is created.

It normally moves through several stages: created, broadcast, unconfirmed in the mempool, included in a block and then buried under more blocks.

Mempool: the waiting room

The mempool is a node’s waiting room for valid but unconfirmed transactions.

There is not one single global mempool. Each node has its own view of the transactions it knows about.

When demand for block space is high, the queue becomes longer. Miners then usually choose transactions with higher fees per amount of data first. The fee is therefore not mainly about how much money you send. It is about the data size of the transaction and the competition for block space.

Confirmations

When a transaction is included in a block, it has one confirmation. When the next block is built on top, it has two confirmations. Each new block makes rewriting that part of the history harder.

For small amounts, a recipient may accept one confirmation. In some cases, a recipient may even accept an unconfirmed transaction, but that carries more risk.

For larger amounts, it is common to wait for several confirmations, often three to six depending on risk level.

How long does it take?

A transaction can often appear in the network within seconds.

The first confirmation arrives on average after about 10 minutes if the fee is competitive, but it can arrive faster or slower because block time is random.

If the fee is too low, the transaction can remain in the mempool for a long time. Many modern wallets help estimate fees. Some also support Replace-by-Fee, which lets you raise the fee on an unconfirmed transaction.

Transactions are hard to reverse

A confirmed Bitcoin transaction cannot be reversed by a bank or customer support team. It can only be paid back by the recipient through a new transaction.

This is a strength when you want final settlement. It is also a risk when mistakes, scams or wrong addresses are involved.

10. Wallets, addresses and private keys

A bitcoin wallet normally does not contain bitcoin in the same way a physical wallet contains banknotes.

The bitcoin is not inside the app. What the wallet manages are private keys, public keys, addresses and transactions.

A keychain is a better analogy

A wallet is more like a keychain than a banknote wallet.

The private key is the key that can sign transactions. The public key and address make it possible to receive bitcoin. Whoever has the private key can, in practice, spend the bitcoin controlled by that key.

Important concepts

Private key: Secret information used to sign transactions. It must never be shared.

Public key: Information that can be used to verify signatures. It is derived from the private key.

Address: A receiving identifier shown by the wallet, often as text or a QR code.

Seed phrase: A list of words that can recreate the wallet’s keys. It should be protected like money.

Seed phrase

Most modern wallets use a seed phrase, often 12 or 24 words.

Those words can recreate the wallet’s keys. That means the words are more important than the phone, computer or hardware wallet.

If someone gets your seed phrase, that person can often take all bitcoin in the wallet. If you lose your seed phrase and also lose access to the wallet, the funds can become impossible to recover.

Addresses and privacy

Bitcoin addresses are long strings of characters. They are often shown as QR codes to reduce the risk of mistakes.

An address should normally not be reused. Reuse makes it easier to connect transactions and analyze your financial activity.

Different wallet types

Exchange account: Easy for getting started, but you do not control the private keys.

Mobile wallet: Convenient for small amounts and practical tests, but the phone must be protected and backup is required.

Hardware wallet: A common choice for larger amounts and long-term storage. It requires correct handling of the seed phrase.

Full node with wallet: Provides high independence and self-verification, but requires more technical knowledge and storage.

Multisig wallet: Several keys are required to spend. Useful for larger holdings, families and businesses, but more complex to set up.

11. Security: self-custody and common mistakes

Bitcoin moves responsibility from institutions to the user. That is part of the point, but it is also one of the largest risks.

Not your keys, not your coins

The phrase “not your keys, not your coins” means that you only have full control over bitcoin when you control the private keys yourself.

If your bitcoin is held on an exchange, you effectively have a claim against the exchange. You do not directly control the keys.

This does not mean everyone must always self-custody everything. For some beginners, a serious service may be safer than badly handled self-custody. But the counterparty risk must be understood.

Common security mistakes

·         The seed phrase is photographed, saved in cloud storage or sent in a chat.

·         The user enters the seed phrase on a fake website.

·         Fake support staff trick the user into revealing keys or making transfers.

·         The user sends to the wrong address without a test transaction.

·         Everything is kept on an exchange with no withdrawal plan or personal backup.

·         A hardware wallet is bought from an unsafe reseller or used without testing the recovery words.

A practical security model

Small amounts: A mobile wallet may be enough. Test transactions and backup with small sums.

Medium amounts: Consider a hardware wallet. Write the seed phrase offline and store it with physical protection.

Large amounts: Consider multisig, geographically separated backups and a documented inheritance plan.

Businesses: Use approval rules, multiple key holders, logging, policies for exchange activity and compliance procedures.

Basic rule: A private key or seed phrase should never be typed into a website, sent to support or stored as an ordinary image file. Anyone asking for it is almost always trying to steal the funds.

12. Bitcoin as payment and Lightning

Bitcoin can be used for payments, but it is important to distinguish between payments made directly on the blockchain and payments made through other layers or services.

On-chain

An on-chain transaction is written into the Bitcoin blockchain.

It is best suited when final settlement, self-custody and larger value transfers matter more than maximum speed. The drawback is that block space is limited and fees can become high when demand is high.

Lightning

Lightning Network is a second layer built on top of Bitcoin.

It uses payment channels where parties can make many payments without every payment being written directly to the blockchain. Channels can later be closed and settled on-chain.

Lightning can make small and fast payments more practical. It also has its own tradeoffs: channel liquidity, online requirements, routing, varying user experience and differences between self-custodial and custodial Lightning wallets.

Bitcoin in commerce

Bitcoin can be used in commerce, but it is not always practical for everyday payments.

The reason is not only technical. In many countries, paying with bitcoin can count as a disposal or taxable event. Each payment may need to be measured in local currency and compared with the cost basis.

This is one reason bitcoin is often used more as savings, value transfer or a technical experiment than as a direct payment method in ordinary retail settings.

13. Bitcoin as savings and investment

Many people buy bitcoin as an investment or long-term savings asset. The most common argument is the limited supply: if demand increases while supply is hard to increase, the price can rise.

That is a possible logic, not a guarantee.

Why some people see bitcoin as digital gold

·         The supply is predefined and difficult to change without broad consensus.

·         The asset can be sent globally without moving physical property.

·         Ownership can be verified cryptographically.

·         One bitcoin can be divided into very small units.

·         Self-custody is possible without a bank or custodian.

Why the risk is high

·         The price can move sharply in a short period.

·         Rules, taxes and banking relationships can affect usability.

·         Self-custody can lead to permanent loss if keys are handled incorrectly.

·         The market is affected by speculation, leverage, liquidity, macroeconomics and sentiment.

·         Scams are common in environments where people chase quick returns.

Avoid price prophecies

A good guide should explain why people assign value to bitcoin. It should not give the impression that future price increases are certain.

Bitcoin has properties that make many people compare it with gold: scarcity, global transferability and easy verification. At the same time, its future value depends on demand, regulation, competition, technical development and user trust.

Practical rule: Never buy bitcoin with money you cannot afford to lose. Do not borrow money to buy bitcoin. Avoid leverage unless you fully understand the risk.

14. Taxes and regulation

This section is a simplified overview. Tax and legal rules vary by country and can change. Always check current rules where you live before you trade, spend, report or build a business around bitcoin.

Taxes for individuals

In many countries, bitcoin is treated as property, a digital asset or another taxable asset rather than as ordinary currency.

A taxable event can occur when you sell bitcoin, exchange it for another crypto-asset, use it to buy goods or services, receive it as income, mine it, earn it through rewards or transfer it in certain business contexts.

The details differ across jurisdictions. Some countries tax capital gains. Some have specific reporting thresholds. Some treat spending bitcoin as a disposal. Some have different rules for long-term holdings, mining, business income or VAT/sales tax.

Record keeping

If you use bitcoin, keep records from the start. Useful records include date, amount, transaction ID, exchange rate, fee, counterparty if known, purpose of the transaction and where the bitcoin came from.

Poor records can become a serious problem later. A wallet may show transactions, but it may not know your cost basis, local tax treatment or whether a transfer was a sale, purchase, gift, payment, self-transfer or business transaction.

Business use

Businesses that accept or hold bitcoin need more structure than private users. They may need accounting policies, valuation procedures, internal controls, customer due diligence, invoice routines, custody policies and clear responsibility for private keys.

A business should not treat a general guide as enough. Use qualified accounting, legal and tax advice before accepting large payments, holding treasury assets or building services around bitcoin.

Regulation and consumer protection

Many jurisdictions now regulate crypto-asset service providers such as exchanges, brokers, custodians and wallet service providers. Regulation can improve standards, but it does not make bitcoin risk-free.

You can still lose money through price declines, scams, bad custody, weak liquidity, bankruptcy of a service provider or your own mistakes.

Important precision: The fact that bitcoin is legal to own in many places does not mean every service is safe, that banks must accept every transaction or that taxes are simple.

15. Common misconceptions

“Bitcoin is anonymous”

Bitcoin is not anonymous in the strict sense.

All transactions are public, traceable and stored permanently. Addresses do not automatically contain names, but if an address is linked to a person, transaction history can be analyzed.

The better word is pseudonymous, not anonymous.

“Bitcoin is free to use”

Creating an address costs nothing, but on-chain transactions have fees.

The fee depends on competition for block space. In some periods fees are low. During high demand, they can become high.

“Bitcoin is unsafe because exchanges have been hacked”

It is important to separate the Bitcoin protocol from companies that handle bitcoin.

An exchange, app or custody provider can have security weaknesses. That does not automatically mean the Bitcoin protocol has been broken.

“Bitcoin is a pyramid scheme”

A pyramid scheme usually requires a central organizer, promises of returns and rewards for recruiting new participants.

The Bitcoin protocol has no central organizer and promises no return. However, scammers often use the word bitcoin to attract victims. The distinction matters: Bitcoin is an open protocol, but criminals can use Bitcoin as bait.

“Bitcoin can never change”

Bitcoin can change, but only if enough users accept new rules.

This makes changes slow and difficult, especially changes that affect fundamental properties such as the supply limit. That inertia is both a strength and a drawback.

“Bitcoin is completely impossible to stop”

It is more accurate to say that Bitcoin is very difficult to stop globally.

Individual countries can ban services, impose strict taxes, block banks or prosecute actors. But an open peer-to-peer network without a central server is harder to shut down than a company.

“Blockchain solves everything”

Blockchains solve certain problems, especially when several parties need to share a history without trusting a central administrator.

For many ordinary systems, a traditional database is faster, cheaper and simpler.

16. Banks, states and financial inclusion

Bitcoin challenges several established assumptions: that money must be created by states, that digital payments must pass through banks and that international transfers must rely on old correspondent banking systems.

Why decentralization can matter

In countries where banks, card payments, mobile identity and public institutions work well, the need for decentralized money can feel abstract.

In countries with high inflation, capital controls, weak institutions or poor access to banking, the issue can be more concrete.

If a bank can freeze an account, if a state can limit withdrawals or if a currency quickly loses purchasing power, the ability to hold and move value in other ways becomes more relevant.

Financial inclusion

Many people in the world still lack stable access to banking services. Others have bank accounts but lack reliable access to international payments, savings tools or secure financial infrastructure.

Bitcoin is not a simple solution to all of this. Internet access, education, safe key management, local liquidity, reasonable regulation and user-friendly wallets are required.

But Bitcoin shows that financial infrastructure can be open, global and permissionless.

Censorship resistance and responsibility

Censorship resistance means that a transaction is hard to stop if it follows the network rules and the user can broadcast it to the network.

This can protect individuals, businesses, journalists, opposition groups and organizations in vulnerable environments. The same property can also be misused.

An honest explanation must include both sides: Bitcoin offers more freedom, but also more responsibility.

17. Energy and environment

Bitcoin uses energy because proof of work requires computation.

This is not a mistake in the system. Energy use is part of the security model. The real question is whether the benefit justifies the cost, which energy mix is used and what alternatives are being compared.

What the energy does

The energy is used to make block production expensive, competitive and verifiable.

A valid block shows that work has been performed. That makes rewriting history difficult and costly.

What the energy does not prove

The fact that Bitcoin uses energy does not automatically mean Bitcoin is good. It also does not automatically mean Bitcoin is bad.

The energy question requires several follow-up questions:

·         What energy source is used?

·         Would the energy otherwise have been wasted or used better elsewhere?

·         What emissions are created?

·         Does mining help stabilize an energy grid or does it stress the grid?

·         What value do users believe Bitcoin provides?

·         What alternative system is being used for comparison?

A balanced conclusion

Bitcoin has a clear energy cost. That should not be denied.

At the same time, the energy use should be explained in relation to the security model, the energy mix and the alternatives. A good guide avoids both marketing slogans and oversimplified criticism.

18. History: Satoshi, the whitepaper and halvings

2008: Bitcoin is described

On 31 October 2008, the document “Bitcoin: A Peer-to-Peer Electronic Cash System” was published under the name Satoshi Nakamoto.

The document describes how digital payments can be sent directly between parties without a trusted third party preventing double spending.

2009: The network starts

On 3 January 2009, the genesis block was created. A few days later, the first working Bitcoin software was released and the network began to be used by a small group of developers and people interested in cryptography.

Satoshi Nakamoto

Satoshi Nakamoto is the pseudonym behind the Bitcoin whitepaper and the early Bitcoin code. The identity is still unknown.

What matters for Bitcoin today is not who Satoshi was, but that the system is open source and that no single person can control the network.

Several people have claimed to be Satoshi. So far, no such claim has been accepted by the broad Bitcoin community as final proof.

Halvings

Bitcoin issuance decreases through halvings. Each halving cuts the block subsidy in half.

·         2009: 50 BTC per block.

·         2012: 25 BTC per block.

·         2016: 12.5 BTC per block.

·         2020: 6.25 BTC per block.

·         2024: 3.125 BTC per block.

·         Around 2140: New issuance is expected to effectively stop when the subsidy rounds down to zero.

Reliability

Bitcoin has had very high reliability since launch, but the claim that the network has never had problems is not exact.

There have been known historical incidents. The important point is that the network recovered, continued to function and became more robust over time.

19. How to get started safely

The best way to understand Bitcoin in practice is to test with a small amount that you can afford to lose.

The goal at the beginning is not speculation. The goal is to understand the flow: buy, receive, back up and send.

Step 1: Learn before you buy

Understand at least the following before you buy bitcoin:

·         The difference between an exchange account and your own wallet.

·         That transactions cannot be reversed like card payments.

·         That the price can fall sharply.

·         That tax reporting can arise when selling, exchanging or spending bitcoin.

·         That seed phrases and private keys must be protected.

Step 2: Choose a way to buy

The most common way to buy bitcoin is through an exchange or broker.

Choose a service with clear fees, reasonable security procedures and the ability to withdraw bitcoin to your own wallet.

Avoid unknown actors, unrealistic return promises and people who contact you on social media to help you invest.

Step 3: Create your own wallet

For very small amounts, a simple mobile wallet is often enough to learn the basics. For larger amounts, a hardware wallet is usually more suitable.

Write down the seed phrase offline. Verify that you can actually restore the wallet before you send larger amounts to it.

Step 4: Make a test transaction

Send a small amount first. Check that the receiving wallet shows the transaction and that confirmations arrive.

Do not send large amounts until you understand addresses, fees, confirmations and backup.

Step 5: Plan for inheritance and emergencies

If nobody else can find or understand your keys after your death, your bitcoin can become permanently inaccessible.

This does not mean you should openly share your seed phrase. It means you need a thoughtful plan for inheritance, instructions and physical storage.

Minimum safe start: Buy a very small amount, send it to your own wallet, restore the wallet from backup and send part of it back. That exercise teaches more than many hours of theory.

20. Questions and answers

Do I have to buy a whole bitcoin?

No. One bitcoin can be divided into 100 million satoshi. You can buy a small fraction of a bitcoin.

Can bitcoin disappear from my wallet?

The bitcoin does not disappear from the blockchain, but you can lose the ability to spend it if you lose your private keys or if someone steals them.

Can someone print more bitcoin?

Not under the current consensus rules. A block that tries to create more bitcoin than allowed should be rejected by full nodes. Rules can theoretically change if users accept new rules, but changing the 21 million limit would be extremely controversial and would likely create a split rather than a simple upgrade.

Is Bitcoin anonymous?

No. Bitcoin is pseudonymous. Addresses are not names, but transactions are public and can be analyzed.

Is Bitcoin legal?

In many countries, it is not illegal for individuals to own bitcoin, but tax rules, reporting rules and regulations for service providers can apply. Always check the rules where you live.

How many confirmations are needed?

It depends on amount and risk. For small amounts, one confirmation may be enough. For larger amounts, three to six confirmations are often used. For very large amounts, a recipient may wait longer.

Can Bitcoin be hacked?

Individual wallets, exchanges, computers and users can be hacked or tricked. Attacking the history of the Bitcoin network itself is a different matter and requires enormous resources. In practical security, user mistakes and custody risk are often larger than protocol risk.

What happens if the internet shuts down?

Bitcoin needs communication between nodes to function normally. During a local internet outage, users in that area may have problems, but the global network can continue if enough nodes and miners can still communicate.

Can bitcoin go to zero?

It can never be completely ruled out. Bitcoin has no guaranteed value and the price is set by the market. For the value to approach zero, trust, demand or usability would need to collapse. Possible causes could include technical failure, harsh regulation, better alternatives, market panic or users no longer seeing value in the system.

Have I missed the train?

That is the wrong question. The better question is whether you understand what you are buying, why you are buying it, what risk you are taking and how you will store it. Buying only because the price has risen or because others talk about Bitcoin is a weak basis for a decision.

21. Glossary

Address

A receiving identifier used to receive bitcoin. An address is often shown as text or a QR code and should normally not be reused.

Altcoin

A cryptocurrency that is not bitcoin.

ASIC

Specialized hardware for a specific type of computation. Bitcoin mining today is mainly done with ASIC machines.

ATH

All Time High. The highest price level recorded for an asset.

Bitcoin

The network, protocol and system.

bitcoin

The currency or asset inside the Bitcoin network.

Block

A collection of transactions added to the blockchain.

Block height

The number of a block counted from the genesis block.

Blockchain

A chain of blocks where each block refers to the previous block with a hash.

Block subsidy

New bitcoin that may be created in a block according to the rules.

BTC

The common abbreviation for bitcoin.

Cold storage

Storage of private keys offline or in a way that reduces exposure to the internet.

Confirmation

When a transaction is included in a block, it has one confirmation. Each block built on top increases the number of confirmations.

Consensus

Agreement in the network about which rules and which transaction history apply.

Custodial

A setup where a third party controls private keys on behalf of the user.

Decentralization

Control and operation are spread across many actors instead of one central party.

Double spending

An attempt to use the same digital money more than once.

Fiat money

State-issued money without fixed redemption for something like gold, such as USD, EUR, GBP or SEK.

FOMO

Fear Of Missing Out. Fear of missing a price increase. Often a poor basis for investment decisions.

Fork

A split in a chain or a split in rules. It can be temporary, a soft fork or a hard fork.

Full node

Software that independently verifies Bitcoin network rules, blocks and transactions.

Genesis block

The first block in a blockchain.

Halving

An event roughly every four years where Bitcoin’s block subsidy is cut in half.

Hash

A digital fingerprint of data.

HODL

Slang for keeping coins long term. It comes from a misspelling of “hold”.

Hot wallet

A wallet where the keys are on an internet-connected device.

KYC

Know Your Customer. Customer identification and due diligence performed by financial actors.

Lightning Network

A second layer on top of Bitcoin for fast and small payments through payment channels.

Mempool

A waiting area for valid but unconfirmed transactions.

Mining

The process where miners create blocks through proof of work.

Multisig

A setup where several private keys are required to spend.

Non-custodial

A setup where the user controls the private keys personally.

On-chain

A transaction written directly to the blockchain.

Private key

A secret key required to sign transactions.

Proof of work

A consensus mechanism where block production requires proven computational work.

Public key

A key that can be used to verify signatures and derive addresses.

Satoshi / sats

The smallest unit of bitcoin: 0.00000001 BTC.

Seed phrase

A list of words that can restore a wallet’s keys.

Self-custody

Personal custody of private keys.

Soft fork

A backward-compatible rule change where the new rules are stricter.

Stablecoin

A crypto-asset that attempts to maintain a stable value against something such as a dollar or euro.

Taxable event

An event that may trigger tax reporting or tax liability, such as selling, exchanging, spending or receiving bitcoin, depending on local law.

UTXO

Unspent Transaction Output. An unspent transaction output that can be used in a new transaction.

Volatility

How strongly the price moves. Bitcoin has historically had high volatility.

Whitepaper

A document that describes a problem and a proposed solution. The Bitcoin whitepaper was published in 2008.