More details here: https://en.bitcoin.it/wiki/Proof_of_work https://en.bitcoin.it/wiki/Proof_of_work https://en.bitcoin.it/wiki/FAQ#How_does_the_proof-of-work_

More details here: https://en.bitcoin.it/wiki/Proof_of_work https://en.bitcoin.it/wiki/Proof_of_work https://en.bitcoin.it/wiki/FAQ#How_does_the_proof-of-work_system_help_secure_Bitcoin.3F https://en.bitcoin.it/wiki/FAQ#How_does_the_proof-of-work_sy... Cracking passwords would require finding data which hashes to an exactly specified value, Bitcoin's proof of work requires finding data which hashes to 'any hash with the given rare property' (given number of leading zeroes, smaller than the target)