Cryptographic data used to verify a signature made by its private key.
Public key meaning
A public key can be shared without revealing the private key. Bitcoin spending scripts use public keys or commitments to them so nodes can verify that an authorized signer approved a transaction.
How it works in Bitcoin
Wallet software derives a public key from a private key using elliptic-curve mathematics. Derivation works in one direction for practical security: knowing the public key does not provide a feasible way to calculate the private key.
A simple example
When an output is spent, the transaction may reveal a public key and signature. Every validating node can check the signature against the transaction data.
Why Public key matters
Wallet terms describe key control, signing and recovery rather than coins stored inside an application. The distinction becomes critical during backup or device failure.
What people often get wrong
A public key and a Bitcoin address are related but not identical. An address usually encodes information used to construct a locking script, often involving a hash or output key.
Quick checks before using the term
- Who controls the spending keys?
- How would recovery work after a lost device?
- Has the backup been tested without exposing it?
Apply these questions to the concrete example above. A precise answer is more useful than repeating the definition without naming the actor, rule or failure path.
Check the primary reference
This entry is written in plain English, but the technical source is available when you need exact protocol detail.
Bitcoin Developer Guide: Wallets ↗