Very interesting. The number six was simply randomly chosen? Or by six confirmations the possibility to do serious damage to the chain is now so statistical large that it becomes impossible in practice? I’m asking, because I always find a fascination on how some standards / values get chosen. Is it based on probability for a given outcome, or just really randomly chosen.
I think 6 is just a commonly used number. There is no rule in the strict sense of the word, but the deeper you go the safer you are. The deeper you go, the more certain you are that your transaction will end up on the consensus chain.
I don't think it's possible even if it's only one block, because the blockchain in the design won't be able to break down and of course it's transparent and that's all the attraction of the blockchain
No, with one block you are not safe. At least in theory, because it can be orphaned. Not sure about 2 blocks, but even 2 blocks can sometimes be orphaned.
That's why there is the rule to wait for 6 confirmations before a payment is confirmed. There is nothing special about the number 6, but it is practically impossible to replace a block that has 6 or more blocks on top of it.
I agree, but it's a ridiculous for small transaction/payment since no sane people would try 51% attack. Most payment service/processor usually set a confirmation as default, while few others even accept 0-conf.
Sure, with small payments you are always safe. No one is going to perform a 51% attack to double spend small amounts. But with large transactions you should wait these 6 blocks.
