The public key is the key that is provided to a third party in Public key encryption, and is paired with the private keys.
With Bitcoin address is a public key (strictly speaking, this is not exactly the case, but that will be explained in more detail later) and when a payment is made from that address, it requires a signature private key.
So, you can think of the owner of an address as the person who owns the private key to that address.
So, it is not possible to ascertain the public key based on its Bitcoin address. It is not possible to confirm the validity of a signature without the public key, so when signing a transaction, the transaction is only written when it is matched with the public key.
In other words, you cannot even know the public key for addresses that have not been used for payment before. The security measures are already quite strong, so the purpose of this procedure is not to improve security but to make Bitcoin addresses shorter and easier to read.
Bitcoin public keys are made using Elliptic Curve Cryptography (ECC).
Learn more on our security site page .