What is Public key?
The value derived from a private key that lets anyone verify a signature without learning the key itself.
Bitcoin uses elliptic-curve cryptography: deriving a public key from a private key is cheap, and reversing it is computationally infeasible.
Addresses are derived from public keys, usually via hashing, which adds a layer of indirection and keeps the public key itself hidden until the coins are spent.
Related terms
Private key
The secret number that authorises spending from an address. Whoever holds it controls the coins…
Keys & custodyAddress
A string encoding the conditions under which an output can be spent. Bitcoin's equivalent of an account…
Keys & custodyDigital signature
Cryptographic proof that the holder of a private key authorised a specific transaction, verifiable by anyone…
This definition is part of the Bitcoin Logical glossary. For the fuller explanation, start with Learn, or see the live numbers on The Bitcoin Signal.