Why nodes need to maintain full list of blocks?

odolvlobo

legendary

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Quote from: bibonix on August 15, 2019, 03:57:34 AM

I mean, why Bitcoin nodes keep all the data of all blocks, back to the genesis block? The majority of this information is not required for processing new blocks and may be ignored. Well, some statistical resources should still keep it, but to run a node it's possible to just delete the majority of historical data. Am I right?

Once a database of the UTXOs is constructed, the blocks are no longer needed. The blocks are kept in order to provide them to other nodes and to reconstruct the UTXO database when necessary. Blocks must also be kept for resolving branches.

spartacusrex

hero member

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I'm just going to say it - It's impossible that there is a fraudulent transaction 1 year behind the top block.

Welsh

staff

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By running exact copies you're assuring that the code hasn't been altered, and the Blockchain hasn't been altered in anyway. There isn't any malicious transactions such as spending on one network, but not spending on another. The copies simply verify that everyone has the same Blockchain. They check against each other for any abnormalities.

ABCbits

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Crypto Swap Exchange

Basically, those blocks are required for verification process such as :
1. Checking whether input is actually exist (not comes from thin air)
2. Checking whether an input is spendable by looking at UTXO scripting

You could ask another node to send their current chainstate, but it won't solve the root problem.

Few relevant question :
https://bitcoin.stackexchange.com/q/43489
https://bitcoin.stackexchange.com/q/72341

bitmover

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bitcoindata.science

Additionally to what other said above

The main reason is trust.

When a new full node comes in, it just needs the Genesis block and then it starts checking all past transactions without trusting anyone but the Genesis block.

If someone decided"after block xxxxx we don't need to verify back transactions anymore" we would need to trust that there is no single malicious transaction in that registry.

Rath_

legendary

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Quote from: bibonix on August 15, 2019, 03:57:34 AM

Well, some statistical resources should still keep it, but to run a node it's possible to just delete the majority of historical data. Am I right?

It is possible to run a node in a pruned mode. Once your node has downloaded all the blocks and verified them, it gets rid of most data. Note that you won't be able to import new addresses and rescan the wallet once you enable it.

bibonix

jr. member

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I mean, why Bitcoin nodes keep all the data of all blocks, back to the genesis block? The majority of this information is not required for processing new blocks and may be ignored. Well, some statistical resources should still keep it, but to run a node it's possible to just delete the majority of historical data. Am I right?

Topic: Why nodes need to maintain full list of blocks? (Read 133 times)