Even if just one comma were different, the block hash would be totally different.
And as every block takes as part of its input the previous block’s hash, every block hash is in a sense a complete history of the blockchain up to that moment.
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Blockchains move in steps, or “blocks”. In Ethereum’s case around once every 13 seconds. All changes made to the blockchain’s state during that time are digested into the block hash, which can be thought of as a unique digital fingerprint:
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