What it is
Bitcoin is a network for recording and validating transfers on a shared ledger. Wallet software uses private keys to authorize spending; mining confirms transactions in blocks. A wallet interface and the network are different things.
A practical distinction
A displayed exchange balance is a claim held through the exchange. Self-custody changes who controls transaction authorization, but also transfers key-management responsibility to you.
Study exercise
Compare a transaction ID, an address and a private key. Record which can be public and which must stay secret. Never enter a real secret into a learning exercise.
Before using any asset
Check the exact network and asset identifier, custody arrangements, liquidity and current provider documentation. These notes explain mechanics and do not recommend buying an asset.
Source: Bitcoin.org: How Bitcoin works. Reviewed 15 September 2026.