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I'm learning about mining and the first thing that surprised me is that the nounce part of the algorithm which is supposed to be randomly looped until you get a number smaller than the target hash .. is just 32 bits long. Can you explain why then is it so difficult to loop an unsigned int and how come is it increasingly difficult over time? Thank you.
Edit: It's been suggested this is a duplicate, this is not. The other question asked if you could run out of nounces, that's nothing to do with my question. My question is about the difficulty of Hashing the exact same 4 billion unsigned int entry loops.