The Finney Attack on Bitcoin is named after Hal Finney. The Finney Attack on Bitcoin is one of the types of double-spending problem. In this Attack on Bitcoin, the Attack on Bitcoiner is the miner who mines blocks normally. In the block, he includes a transaction which sends some of his coins back to himself without broadcasting the transaction. When he finds a pre-mined block, he sends the same coins in a second transaction. The second transaction would be rejected by other miners, but this will take some time. To prevent this Attack on Bitcoin, the seller should wait for at least six blocks confirmation before releasing the goods.
Another Attack on Bitcoin the trader or merchant is exposed to when accepting payment on 0/unconfirmed. The Finney Attack on Bitcoin is a fraudulent double-spend that requires the participation of a miner once a block has been mined. The risk of a Finney Attack on Bitcoin cannot be eliminated regardless of the precautions taken by the merchant, but some miner hash power is required and a specific sequence of events must occur. Just like with the race Attack on Bitcoin, a trader or merchant should consider the cost / benefit when accepting payment on just one confirmation when there is no recourse against the Attack on Bitcoiner.
A Finney Attack on Bitcoin works as follows: Suppose the Attack on Bitcoiner is generating blocks occasionally. in each block he generates, he includes a transfer from address A to address B, both of which he controls. To cheat you, when he generates a block, he doesn’t broadcast it. Instead, he opens your store web page and makes a payment to your address C with his address A. You may wait a few seconds for double-spends, not hear anything, and then transfer the goods. He broadcasts his block now, and his transaction will take precedence over yours.