What Is Bitcoin?
Understand Bitcoin's purpose, supply, transactions, and proof-of-work security.
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What to remember
- Bitcoin is both a network and the asset recorded by that network.
- Transactions are authorized with private keys and verified by network participants.
- Proof of work secures agreement through computational cost.
- Price, custody, fees, and transaction confirmation are separate questions from the protocol's core design.
Bitcoin in plain language
Bitcoin is a digital asset and payment network that lets people transfer value without a central bank maintaining the ledger. Its rules are implemented by open-source software, and independent computers verify transactions and keep copies of its blockchain.
How ownership works
The Bitcoin network records which addresses can spend particular units. A wallet uses a private key to create a digital signature; the network checks that signature before accepting a transaction. The wallet does not contain coins physically: it manages the credentials used to control an on-chain balance.
Mining and proof of work
Bitcoin uses proof of work. Miners compete to find a valid result for a computational puzzle, and the winning miner proposes a block of transactions. Other participants verify the block against Bitcoin's rules. The competition makes rewriting settled history costly, although it does not make the network immune to every risk.
Supply and halvings
Bitcoin's software limits the eventual issuance to 21 million bitcoin. New issuance is paid to successful miners and decreases at scheduled block intervals known as halvings. The market price can still change substantially; a fixed issuance rule does not guarantee a particular value.
"Fixed supply" is not the same as "guaranteed value"
A capped issuance schedule controls how many new bitcoin can ever exist — it says nothing about demand. Price still moves on how many people want to hold or use bitcoin at any given time, which can rise or fall independently of the supply schedule.
What to remember
- Bitcoin is both a network and the asset recorded by that network.
- Transactions are authorized with private keys and verified by network participants.
- Proof of work secures agreement through computational cost.
- Price, custody, fees, and transaction confirmation are separate questions from the protocol's core design.
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