A confirmation is when a transaction exists in a block. Each subsequent block further confirms that transaction. 6 confirmations means that the transaction exists in a mined block and 5 other blocks were found thereafter. Remember, each block references the previous which makes this chain stronger. Its mathematically sound to allow for
- 0 confirmation purchases under $20,
- 1 confirmation <$100,
- 2 confirmations for a nice TV,
- 3 confirmations for a vacation package,
- 4 confirmations for a car,
- 5 confirmations for a house, and
- 6 confirmations for a fighter jet.
A double spender would have to computationally create new blocks to create the longest chain it would be more expensive to try to double spend this way.
A confirmed transaction is one in which the
ENTIRE network has signed off on by including it in a block. 0 confirmations just means the transaction has been broadcast and miners should include it while trying to find the next block.