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I've read through some explanations saying that every client in the network knows every transaction because when someone wants to perform a transaction, he sends that informationen (how much, to whom and his own address) to everybody he knows and everybody they know and every.... and so on. Until it gets confirmed by everybody in the network. Then the transaction can take place. So everybody in the network knows that this transaction happens, and add the new block to their chain.
Does REALLY everybody have the whole history of transactions (a.k.a one HUGE chain of blocks) stored on their (lets say) computer?
Really all? Isn't this amount of bytes too much for normal hard disks (in my computer, smartphone, ...) considering ALL transactions which have ever happened and happen?
The whole blockchain is encrypted, right? But who got the key? – watchme – 2018-03-30T11:14:49.317
The blockchain itself is not encrypted. Actually, it's the opposite... it's all public. What gets encrypted is each person's address and the key is known as your "private key." – Nicolas Lopez – 2018-03-30T11:19:07.923
1And to your answer: So my bitcoin wallet doesn't store every transaction which has ever happened. But it includes my transaction right? Or does it not include any transaction because all my transactions are added to the one big blockchain there is? – watchme – 2018-03-30T11:23:57.547
It's all or nothing. Unless you're running the Bitcoin Core software on a powerful machine (you would know it if you were), your wallet doesn't store any transactions... even your own. The transaction is stored on those running the full BC node. However, your wallet may have some functionality that shows you what coins you've sent and received, but it only does this to help you as a user and isn't necessary for the network to function. – Nicolas Lopez – 2018-03-30T11:34:33.997
and those full-nodes check all transactions and do the mining? – watchme – 2018-03-30T12:03:07.873
Yes and those that run full nodes can farm out the mining into different pools. – Nicolas Lopez – 2018-03-30T12:12:31.130
The question is about storing the chain, not just downloading it. Perhaps you can clarify in your answer that while full nodes don't trust anyone so they have to validate all of history, they do not need to store all of it (pruning mode). – Pieter Wuille – 2018-03-31T13:35:32.050
Before I do that, let me get it right. So with pruning mode you have to download the chain, but not store it? Instead they just merkle tree to validate the history? – Nicolas Lopez – 2018-04-01T23:10:59.487