Can someone explain me how the confirmations for transactions work in a technical manner? (or you can link me to a blog page or an article..)
Bitcoin confirmations are the number of blocks in the blockchain that have been accepted by the network since the block that includes the transaction. Literally, it represents the difficulty of a double spend attack. With zero confirmations no proof of work has been done, so you can't tell if anyone considers the transaction valid. Even with a single transaction it is possible for an attacker to pre-compute a single block.
After a transaction is broadcast to the Bitcoin network, it may be included in a block that is published to the network. When that happens it is said that the transaction has been mined at a depth of 1 block. With each subsequent block that is found, the number of blocks deep is increased by one. To be secure against double spending, a transaction should not be considered as confirmed until it is a certain number of blocks deep.
