Newb question: What is a hash? How is it generated?
Hash is a mathematical algorithm that takes a large data of any size, make a calculation and create another smaller and fixed size data as output. It is designed to be a one-way function, that is hard or almost impossible to be reverted.
In Bitcoin we use "secure hash algorithm 256". Bitcoin miners need to produce proof of working buy solving the puzzle to be rewarded. They need to combinate all the inputs ( the most recent transactions+timestamp+reference of the previous block ) with their own Nonce. The combination of Nonce + inputs is tried several times. When the hash value with less or equal to the target of the network is found the miner is rewarded.
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