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i want to know whether block is a combination of transaction verified by one node so all the transaction in that block is verified and once node is full node will broadcast it or any node can add transaction in that block?
verified transaction in a block is verfied by one node?
Answers
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In the world of blockchain, no one trusts anyone. Transactions in each and every block are verified by each and every node.
Just the node that solves the cryptographic puzzle (In PoW), gets a chance to append a new and valid block to the blockchain. Which in turn will be verified by every node.
you u means there are 2 verification ? one for valid transaction and one for adding valid block in ledger ? so miner or node is getting reward for both ? – ameet – 2018-02-27T02:47:00.260
1Let's put it this way. Miner gets reward only and only if it adds a new block to blockchain. And block must contain all valid transactions. If it contains invalid transaction then other nodes will check the transaction and on finding transaction invalid they won't accept new block. – Preet – 2018-02-27T04:03:08.443
A miner has to generate a block that other nodes will consider valid or nothing will happen to his block and he won't get any reward. When nodes receive blocks from other nodes, they confirm that the new block complies with all system rules which includes a rule that every transaction in that block be valid. Miners can put anything in the blocks they mine that they want and nobody else can alter them (or it would be a totally different block and not the one they mined) but if they break any validity rules, all honest clients will ignore the block and they'll get no reward. – David Schwartz – 2018-10-31T17:09:55.793
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As per my comment, I will anyhow try to provide a short, general answer: @Preet has already given good info. So the bitcoin network consists of miners (which also run a full node), and thousands of full nodes not running mining software. The miners have one and only one task, to make sure valid transactions are assembled into a new block. When the block is then sent to the network, each full node verifies this block, to be sure the miner was not misbehaving (provided a faulty tx).
The full node would verify the block and each tx inside, based on these rules. You may also read about protocol rules in this webpage. This second set of checks by full nodes is required, for consistency. Two main reasons come to my mind: as a merchant, I want to know, that there is only valid tx in the blockchain, and if a miner sends wrong blocks, it's IP address will be added to the list of misbehaving hosts, and eventually be banned (no more tx sent to this host). If a misbehaving miner doesn't receive tx, he is out of business, loosing all his invest into mining hardware.
This is one of the most important things to understand in bitcoin concept: it is more beneficial to play the game, as trying to play against the system.
Welcome to bitcoin.SE! The provided information is somehow difficult to understand, as it seem to mix two or three questions. How to raise a good question, which increases the probability for a good answer, see here: Have a look at https://bitcoin.stackexchange.com/help/how-to-ask.
– pebwindkraft – 2018-02-27T08:23:30.107