Pay-To-Public-Key (P2PK)

Pay-to-Public-Key is the simplest form to make a transaction on the Bitcoin blockchain. The sender forwards his funds from his wallet directly to the public key of the recipient. The receiver just needs to prove that he is the owner of the public key and he/she can spend the tokens. The only op_code used in this transaction is OP_CHEKSIG, which checks if the private key corresponds to the public key. If the check is valid, the user can freely spend the funds in future transactions.

The advantages of this script are its simplicity and compatibility. Because with Pay-to-Public-Key the public key is publicly visible, there is one less layer of security. It’s still highly unlikely for a hacker to crack the Elliptic Curve Digital Signature Algorithm, which Bitcoin uses, but advances in quantum computing could crack that algorithm with today’s technologies. A public key has a length of 64 characters, where the Bitcoin public address has a length between 26-34 characters with a built-in error check. These are the two main reasons why the Pay-to-Public-Key script is no longer or rarely used on the Bitcoin blockchain.