I can see that my bitcoin transfers becomes real when my exchange detects 2 or more confirmations.
I believe each confirmation is a validation. Am I correct? If so, How many confirmations will have my transaction? As many as miners does exist? If not, how many?
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Each node validates all transactions in every block and, every block in its entirety.
The confirmation count is how many blocks are mined on top of the block that includes your transaction. A new block is mined every ten minutes on average.
It is a representation of the number of blocks present in the blockchain which are now accepted by the by the network since the block that includes the transaction. There is not actual authority to determine whether the transactions is valid or invalid, so the recipient uses number of confirmations as a way of protecting against double-spend attacks.
The network always try to extent the blockchain, so that some chain may win. The deeper the transaction is in the chain, the higher the chance it will win because the network tries very hard not to duplicate efforts. It is mandatory for the attacker to match the power of entire bitcoin network to get along with the block generation, as the difficulty level keeps on increasing with the increase in the block else it will get difficult for the hacker to forge the transaction.
Technically, the more nodes to confirm the transaction, the safer you are from any hacker. So feel please when more than 2 miners verify your transaction. As the more verifications, the higher are the chances that transaction will remain in the public hash chain rather than a conflicting transaction if there was one.
Say your transaction is in block number n; as more and more proof of work is added on top of the block n (by means of block mined on top of it) the probability that someone proposes a longer chain that does not contain your transaction at block height n decreases as blocks are mined on top of block n.
This is due to the fact that whoever wants to propose an alternative chain that differs from the active chain starting from height n, has to provide valid proofs of work for every block starting from n, before someone further extends the active chain, which happens on average every 10 minutes.
Each confirmation is a valid block mined on top of block n; confirmations make what is written in n harder and harder to change as time passes.
