5) hashing:

- hashing involves a miner taking a summary of the list of transactions in a block, the hash of the previous block, a random number called a nonce, and putting it all through a hashing algorithm (like SHA-256).
- this spits out a 64 digit hexadecimal number that may or may not meet the requirements of the Bitcoin software
- it is very unlikely to find the right hash, which means that hashing/mining uses a large amount of computational power and electricity
- this ensures miners’ commitment to faithfully verifying blocks because they are spending resources (money) to mine blocks
- the energy intensive nature of mining and hashing also deters attacks, as gaining control of 51% of the nodes in the network would be extremely expensive. possibly so expensive that it wouldn’t even be worth it to attack the network