A public key is the public part of a cryptographic key pair and is mathematically related to the corresponding private key. In digital-signature systems, the public key is used to verify that a signature was produced by the corresponding private key.

In some blockchain systems, a wallet address is derived directly or indirectly from a public key. However, a public key and an address are not universally interchangeable concepts: the exact address construction depends on the blockchain protocol and address standard.

Unlike a private key, a public key is not intended to remain secret. Revealing it does not by itself allow someone to sign transactions. The security model relies on the computational difficulty of deriving the private key from the public key.