In plain English
What Public key means
A public key can be shared because it is designed to confirm that a signature matches its related private key without revealing that private key. Many blockchain systems display addresses rather than raw public keys, and the exact relationship differs by protocol. A public key is therefore not always identical to the address a sender uses.
Why it matters
The public-key system allows a decentralized network to verify authorization without asking a bank or broker to approve each transfer. It also explains why a recipient can share an address to receive assets while keeping the credential needed to spend those assets secret.
Example
Nora provides a receiving address to a customer. The customer sends tokens to that address. Later, when Nora spends those tokens, her wallet produces a signature using the matching private key; network validators verify that signature using public-key cryptography. The customer never needs access to Nora’s private key.
Quick answers
Common questions
Is a crypto address always a public key?+
No. On many networks, an address is derived from a public key or a script and is encoded for receiving funds. The precise format and relationship depend on the blockchain protocol.
Can someone spend crypto with only a public key?+
No. A public key can help verify a signature, but spending ordinarily requires a valid signature from the corresponding private key or another authorization mechanism specified by the account or smart contract.
Sources