From what i read previously, it is due to avoid something called double spend, even i am not sure how is it work, but its something like in the
olden days where ATM in Location A and Location B is not centralized and sync, so people can withdraw their initial deposit twice.
I think its something like that if i am not mistaken
olden days where ATM in Location A and Location B is not centralized and sync, so people can withdraw their initial deposit twice.
I think its something like that if i am not mistaken
it's not only about double spend or 51% attack, there are other attacsk that can be done at 4 or 5 confirmations and lower, i think it was called the finney attack in his memory, so to avoid this bitcoin has 6 depth confirmation
I have read mostly the 51% attack but i think this is the first time I read about this finney attack. So I googled it and see this result. This is kinda tricky because it does not need 51% of the hashrate to do the attack. For explanation you can read this. http://bitcoin.stackexchange.com/questions/4942/what-is-a-finney-attack
Some of the notable description on that link
Code:
The Finney attack is named after Hal Finney, who suggested it in this comment. (Hal happens to be the first recipient of a Bitcoin
transaction, and AFAICT the first person to comment on Bitcoin.)
It is a double spending attack with the following features:
It only works if the merchant accepts unconfirmed transactions.
It still works, however, if the merchant waits a few seconds to verify that everyone in the network agrees he was paid.
It requires the attacker to be mining and controlling the content of his blocks; however, he can in theory do this with any hashrate,
in particular significantly less than 50% of the network hashrate
