Bitcoin explained: the white paper, how it works and who made it

In short: Bitcoin is digital money that exists only on computers. Instead of a bank keeping the record, many computers share one public record of every payment.^[1][2]

• Bitcoin is a cryptocurrency, a kind of digital money that generally exists only electronically. There are no Bitcoin coins or bills to hold.^[1]3–5
• People keep bitcoin in a digital wallet. Each wallet has an address, usually a long string of numbers and letters.^[1]3–5
• Bitcoin was designed so that payments go straight from one person to another, without a bank or payment company in the middle.^[2]6–8
• Every payment is recorded in a shared record called the blockchain, a growing chain of blocks of transactions.^[2]6–8
• The U.S. government does not back Bitcoin, and cryptocurrency held in accounts is not insured by the government the way bank deposits are.^[1]Teens

This page writes “Bitcoin” for the system and “bitcoin” for the units people send. For cryptocurrency in general, see What is cryptocurrency?

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In short: On October 31, 2008, someone using the name Satoshi Nakamoto shared a short paper, “Bitcoin: A Peer-to-Peer Electronic Cash System,” describing electronic cash that can be sent online without a trusted third party.^[1][2]

When and where it was published

The message, titled “Bitcoin P2P e-cash paper,” went to The Cryptography Mailing List on Friday, October 31, 2008. It described a system that was “fully peer-to-peer, with no trusted third party” and linked to the paper.^[1] The paper is short: 12 numbered sections and 8 references.^[2] You can read the original white paper (PDF, bitcoin.org). UpOnly Learning links to it and does not copy it.

The problem it solves: double spending

Digital files are easy to copy, so digital money risks being spent twice: double spending. Online payments relied on banks as trusted third parties to keep the record.^[2] The paper’s idea: announce every transaction publicly and let the network agree on one history of which payment came first, so later attempts to spend the same coins are rejected.^[2]

The paper, section by section, in plain language

1. Introduction. Online payments depend on trusted middlemen and can be reversed, which adds costs. The paper asks for payments based on cryptographic proof instead of trust.^[2]
2. Transactions. A coin is a chain of digital signatures: each owner signs it over to the next owner’s public key. The catch: the receiver cannot tell alone whether it was already spent.^[2]
3. Timestamp server. Take a block of transactions, compute its hash (a short digital fingerprint) and publish it. Each new timestamp includes the one before it, forming a chain.^[2]
4. Proof-of-work. Computers try number after number until a block’s hash starts with enough zeros, an idea from Adam Back’s Hashcash. It is “one-CPU-one-vote”: the longest chain, with the most work, wins.^[2]
5. Network. In six steps, nodes broadcast transactions, gather them into blocks, do the work and share finished blocks. Others accept a block only if its transactions are valid and unspent, then build on it.^[2]
6. Incentive. Each block’s first transaction creates new coins for its maker, like gold miners adding gold. Fees are a second reward. Playing by the rules should pay better than cheating.^[2]
7. Reclaiming disk space. A Merkle tree lets old transactions be trimmed. A block header is about 80 bytes, or about 4.2MB per year.^[2]
8. Simplified payment verification. Keeping only the block headers of the longest chain is enough to check that a payment was accepted.^[2]
9. Combining and splitting value. Like cash, a transaction can combine smaller amounts and has at most two outputs: the payment and the change.^[2]
10. Privacy. Everyone can see that an amount moved, but public keys stay anonymous, like a stock exchange listing trades without names. Use a new key pair for each transaction.^[2]
11. Calculations. An attacker with less computing power falls further behind as blocks are added. With 10% of the power, the chance of catching up from 5 blocks behind is under 0.1%.^[2]
12. Conclusion. A system for electronic transactions without relying on trust. Nodes can leave and rejoin at will and vote with their computing power.^[2]

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In short: Bitcoin was created by someone using the name Satoshi Nakamoto. It is a pseudonym, a made-up name, and the person or group behind it remains a mystery.^[1]

• The white paper and the email that announced it were signed “Satoshi Nakamoto.”^[2][3]3–5
• Satoshi Nakamoto is a pseudonym, not a confirmed real name.^[1]6–8
• Some people have claimed to be Satoshi. In 2024, the High Court of England and Wales ruled on one claim: it declared that Craig Wright is not the author of the Bitcoin white paper, did not operate under the name Satoshi Nakamoto between 2008 and 2011 and did not create the Bitcoin system.^[4]Teens
• The judge announced this in March 2024 and gave his reasons in writing on May 20, 2024.^[4]Grown-ups

A lesson for students: the paper describes a system that does not rely on trusting any one person,^[2] which is why Bitcoin keeps running while its creator stays unknown.

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In short: Payments are grouped into blocks, miners compete to add each block, and private keys prove who can spend which bitcoin.^[1][2]

Blocks and the blockchain

• New payments are broadcast to the network and collected into a block. Each block points back to the block before it, so the blocks form a chain.^[1]6–8
• Bitcoin’s software aims for one new block about every 10 minutes and adjusts the puzzle difficulty every 2,016 blocks to stay near that pace.^[3][2]Teens

Mining

• Miners add blocks by solving hard cryptographic puzzles that take a lot of computing power. In exchange, they earn transaction fees and newly created coins.^[4]6–8

Keys and wallets

• A wallet is software that stores a user’s keys and addresses and adds up how much they hold.^[2]6–8
• A private key works like a secret signature for payments. If a user loses a private key, the bitcoin linked to it is lost, because the key cannot be made again.^[2]Teens
• Payments usually cannot be reversed. Bitcoin sent to the wrong address or a scammer comes back only if the receiver returns it.^[5]Teens

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In short: No more than 21 million bitcoins can ever exist. New ones come from block rewards, and the reward is cut in half about every four years.^[1][2]

• The first block, called the genesis block, carries the date January 3, 2009, and a newspaper headline from that day: “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks.”^[3]6–8
• The first block reward was 50 bitcoins.^[3]6–8
• The reward halves every 210,000 blocks, about every four years. This is called the halving.^[3][2]6–8
• The total supply is capped at 21 million bitcoins, as both the Bank for International Settlements and a 2025 White House executive order describe it.^[1][4]Teens

Each row is half the one before. Keep halving forever and the total gets closer and closer to 21 million but never passes it.^[3][1]

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In short: Bitcoin went from an email to a mailing list in 2008 to investment products approved for U.S. exchanges in 2024.^[1][2]

1. Oct 31, 2008 Satoshi Nakamoto shares the white paper on The Cryptography Mailing List.^[1]
2. Jan 3, 2009 The genesis block, Bitcoin’s first block, is time-stamped.^[3]
3. 2014 IRS Notice 2014-21 says virtual currency is treated as property for federal taxes.^[4]
4. Sep 17, 2015 The CFTC finds, for the first time, that Bitcoin and other virtual currencies are commodities.^[5]
5. Jan 10, 2024 The SEC approves the listing and trading of spot bitcoin exchange-traded products.^[2]
6. Feb 1, 2024 The U.S. Energy Information Administration estimates that crypto mining used 0.6% to 2.3% of U.S. electricity in 2023.^[6]
7. May 20, 2024 A UK High Court judgment gives the reasons why Craig Wright is not Satoshi Nakamoto.^[7]
8. Mar 6, 2025 A White House executive order sets up a Strategic Bitcoin Reserve from bitcoin the government obtained through forfeiture.^[8]

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In short: Bitcoin’s price can swing fast, scammers often ask for it, a lost key usually means lost coins, and mining uses a lot of electricity.^[1][2][3][4]

Price swings

• Cryptocurrency values change constantly, and the Federal Reserve describes them as subject to extreme price volatility.^[2][1]6–8
• UpOnly Learning does not predict prices. Money lost in a price drop may not come back.^[2]Teens

Scams

• Only scammers demand payment in cryptocurrency. A stranger online who asks for bitcoin is a warning sign.^[2]3–5
• In 2024, the FBI’s Internet Crime Complaint Center received 149,686 complaints involving cryptocurrency, with $9.3 billion in reported losses. Investment fraud made up $5.8 billion of that.^[5]Teens

Lost keys and no insurance

• There is no “forgot password” button for a private key. Lose the key, and the bitcoin linked to it is lost.^[3]6–8
• Cryptocurrency held in accounts is not insured by the government.^[2]6–8

Energy use

• The EIA estimated that crypto mining used 0.6% to 2.3% of all U.S. electricity in 2023, as much as more than 3 million to more than 6 million homes. These are early estimates.^[4]6–8
• In 2018, the Bank for International Settlements compared Bitcoin mining’s electricity use to that of Switzerland.^[6]Grown-ups

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In short: The IRS treats bitcoin as property, the CFTC treats it as a commodity, and the SEC oversees investment products tied to it.^[1][2][3]

• For U.S. taxes, digital assets such as bitcoin are property, not currency. The IRS first said so for virtual currency in Notice 2014-21.^[1][4]Teens
• Federal tax returns ask a yes-or-no question about whether the filer received, sold or exchanged a digital asset during the year.^[1]Teens
• The general tax rules for property apply when bitcoin is sold, exchanged or spent. Ask a tax professional about a specific case.^[4]Grown-ups
• The CFTC, which oversees commodity markets, found in 2015 that Bitcoin and other virtual currencies are commodities.^[2][5]Teens
• On January 10, 2024, the SEC approved the listing and trading of several spot bitcoin exchange-traded products, often called bitcoin ETFs. The SEC chair said the agency “did not approve or endorse bitcoin” and urged investors to stay cautious.^[3]Teens

For crypto rules in general, see Crypto rules and Who protects your money?

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In short: Start with what money is, then add shared records, then keys and risks. Each step builds on the one before.^[1][2]

• K–2: money can be numbers. Money can be coins, bills or numbers on a computer, and Bitcoin is money that lives only on computers.^[1] Try it: pay for a pretend snack with a $1 bill, then with a number on a card, and talk about why both can work.K–2
• Grades 3–5: one shared notebook. Picture a class notebook of sticker trades that every student copies. Trade the same sticker twice and the copies show it. Bitcoin’s shared record works the same way.^[2] Safety rule: tell a trusted adult if anyone online asks for bitcoin, because only scammers demand crypto.^[1]3–5
• Grades 6–8: keys and halving math. A private key is like a password that can never be reset.^[3] Then work through the halving table on this page, 50, 25, 12.5, 6.25, and ask students why the total never passes 21 million.^[4][5]6–8
• Teens: read the source. Read the abstract and section 2 of the white paper and ask: what problem does it solve, and who must you trust? Then review the risks and rules above.^[2][6]Teens
• Grown-ups: keep it neutral. Try: “Let’s see what the white paper and the regulators say.” Be firm only about scams, because crypto payments usually cannot be undone.^[1]Grown-ups

Next: spotting money scams and personal finance for teens.

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