Public Key

Definition

A public key is the shareable component of an asymmetric cryptographic key pair. In cryptocurrency signature systems, it lets others check that a signature was produced using the corresponding private key without revealing that private key. Bitcoin derives public keys through elliptic-curve operations and uses them in spending conditions, sometimes directly and sometimes through commitments or hashes. A public key is not always identical to a receiving address, because addresses can encode different kinds of output information. Knowing an ordinary public key does not normally provide spending authority, but publishing it can still reveal relationships between transactions or wallet activity. Extended public keys used by hierarchical wallets can expose considerably more information than a single key. Verification also establishes a relationship to a cryptographic key, not necessarily to a named individual. Real-world identity requires additional evidence outside the key's mathematical properties.