A public key in Bitcoin is a string of characters that is derived from a corresponding private key, and it is used to receive funds. A public key is derived from the private key through a process known as elliptic curve multiplication, which is a mathematical function that is difficult to reverse.
Each public key has a corresponding Bitcoin address, which is a shorter string of characters that can be shared publicly. A Bitcoin address is derived from the public key through a process that involves applying a series of cryptographic algorithms to the public key.
When someone wants to send Bitcoin to a particular address, they broadcast a transaction to the Bitcoin network, which includes the recipient’s public key (or Bitcoin address) and the amount of Bitcoin being sent. Miners verify the transaction and add it to the blockchain, which updates the balances associated with the relevant public keys.
It is important to note that while public keys can be shared freely, they cannot be used to derive the corresponding private key. Only the person who possesses the private key can use it to authorize transactions and send Bitcoin from that address. Therefore, it is crucial to keep the private key secure and not share it with anyone else.