TERM_DEF // BITCOIN_BASICS / BITCOIN_CORE
BITCOIN
CORE
CORE
bitcoin-core/">Bitcoin Core. The reference implementation of the Bitcoin protocol; running it gives you a node/">full node that validates every rule from genesis.
This page sits in the Bitcoin Basics section — The vocabulary you meet on day one — what Bitcoin is and the pieces that make it move. Read on for what it is, why it exists, how it works under the hood, and what to watch out for.
This page sits in the Bitcoin Basics section — The vocabulary you meet on day one — what Bitcoin is and the pieces that make it move. Read on for what it is, why it exists, how it works under the hood, and what to watch out for.
WHAT_BITCOIN_CORE_IS
Bitcoin Core — at a glance
BITCOIN BASICS
Bitcoin Core is one of the foundational ideas in Bitcoin — the vocabulary you meet on day one. The reference implementation of the Bitcoin protocol; running it gives you a full node that validates every rule from genesis. Before going deep on transactions, scripts, or mining, every reader needs a working mental model of these basics, because every later concept is built out of them.
Why it exists
DESIGN
Bitcoin is what you get when you replace every trusted intermediary in money — banks, governments, payment processors — with cryptography and a peer-to-peer-p2p/">peer-to-peer network. The basics exist because the system needs a small set of agreed-upon terms ("block", "address", "node", "transaction") so software, miners, exchanges, and users can talk to each other without a central authority defining anything.
HOW_IT_WORKS
Mechanism
HOW IT WORKS
Mechanically, Bitcoin Core is part of a feedback loop: full nodes validate the rules; miners produce blocks that follow the rules; wallets build transactions that obey the rules; users send and receive without asking permission. No one is in charge, yet everyone agrees on the state — because the rules are deterministic and every node enforces them itself.
1. The user installs a wallet (or runs a full node) — software they fully control.
2. The wallet derives keys from a seed; the keys generate addresses; the user receives coins to those addresses.
3. To spend, the wallet builds a transaction that proves ownership of those coins, signs it locally, and broadcasts.
4. Miners batch transactions into blocks; the network agrees on which blocks form the chain via proof-of-work.
5. ~10 minutes later the transaction is in a block; another ~50 minutes later, it is buried under 6 confirmations.
6. No intermediary, no permission, no reversal — the entire system is verified by software the user runs themselves.
WORKED_EXAMPLE
Bitcoin in numbers
EXAMPLE
total supply : 21,000,000 BTC (fixed forever — hard cap)
smallest unit : 1 satoshi = 0.00000001 BTC (10⁻⁸)
block time : ~10 minutes target (auto-adjusted)
block reward : 3.125 BTC subsidy + fees (2024–2028)
network nodes : ~17,000 full nodes worldwide (Bitnodes)
hashrate (2024): ~600 EH/s = 600 quintillion hashes / second
transactions : ~250,000–500,000 / day on-chain (excluding Lightning)
genesis block : 2009-01-03 "Chancellor on brink of second bailout for banks"
KEY_PROPERTIES
NO ADMINISTRATOR
No one can freeze your funds, reverse a confirmed payment, or change the rules unilaterally.
Every line of the reference client (Bitcoin Core) is public; auditing is permissionless.
HARD-CAPPED SUPPLY
GLOBALLY ACCESSIBLE
Anyone with internet (or a satellite radio + sneakernet) can transact. No KYC for the protocol itself.
COMMON_PITFALLS
Things that catch people out
PITFALLS
- "Bitcoin" the protocol and "BTC" the asset are different things — software handles the protocol, exchanges trade the asset, and users hold the keys.
- Beware projects that call themselves "Bitcoin X" — the only Bitcoin is the one whose chain extends from the 2009 genesis block by Satoshi.
- "Decentralised" is a property of the consensus protocol, not of the exchanges that custody most coins. Self-custody is what makes it personally decentralised.
RELATED_CONCEPTS
Other terms from Bitcoin Basics — click any to read its page:
TERMINOLOGY_INDEX
TERMINOLOGY
Bitcoin Core
The reference implementation of the Bitcoin protocol; running it gives you a full node that validates every rule from genesis.
Bitcoin
A peer-to-peer digital cash system where coins are entries in a public ledger that anyone can verify and no one controls.
BTC
The ticker symbol for one bitcoin; one BTC equals 100,000,000 satoshis, the smallest divisible unit.
Satoshi (unit)
The smallest unit of bitcoin (1 sat = 0.00000001 BTC); all on-chain amounts are stored as integer satoshis to avoid floating-point errors.
Satoshi Nakamoto
The pseudonymous author of the 2008 Bitcoin whitepaper and the original Bitcoin software; their identity remains unknown.
Blockchain
An append-only chain of blocks where each block commits to the previous one via its hash, making history tamper-evident.
Decentralization
No single party can change the rules or freeze funds, because thousands of independent nodes each validate every transaction themselves.
Peer-to-peer (P2P)
A network where every participant talks directly to other participants, with no central server in the middle.