Public-key cryptography creates a public and a private key for each user, using a one-way hash function to create the public from the private key. The public keys are used by the sender and receiver of a transaction to identify each other. Private keys remain undisclosed, and are used by the sender and receiver to sign and verify transactions, respectively. Here, User 1 sends a transaction to User 2, using User 2’s Public key. User 2 receives the transaction, identified as having been sent by User 1’s public key.