How do difficulty, hashrate, and network hashrate fit together?

Question

I understand that there are multiple terms for the idea of how hard it is to successfully mine BTC. The terms I have seen are "difficulty", "network hashrate" and "hashrate". I am not entirely sure what the differences between these are.

On my computer, I can call SHA256 on a string. How many such input strings would I need to try right now before I would get lucky enough to successfully propose a block? And this number of tries, how is it related to "difficulty", "network hashrate" and "hashrate"?

Answer 1

To create a new block, miners have to construct a block and, from that block, calculate a number using a mathematical function called a hashing function. The calculated number is called a hash. If the hash is bigger than the current network target, the miner changes the constructed block, for example by choosing a different number for a part called a nonce, and recalculates.

The hashrate is the number of hashes that can be calculated in one second. There is a hashrate for each mining device and a total hashrate for the whole bitcoin network

If there is too much mining power, new blocks could be calculated too fast for the other bitcoin wallets to keep up. So the difficulty is increased by making the target smaller

To find a block whose hash is less than the target you might need to try hashing 9223372036854775807 different blocks on average or you might get lucky on the first try.