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The whole point of a blockchain is that it's append-only. Each block has a hash of the previous block. If you wanted to modify a Bitcoin block from a year ago,
by chroma 9y ago
The whole point of a blockchain is that it's append-only. Each block has a hash of the previous block. If you wanted to modify a Bitcoin block from a year ago, you'd have to do the same computation as a year worth of all miners.
- Dylan16807 9y agoThe blocks are hash trees, and you don't need to store the whole tree. Purging depends on that, not altering the block history.