A hash function is one of the cryptographic primitives used to “protect communication in the presence of adversaries” (Gensler, Fall 2018). The same input will always provide the same output, a string of 0’s and 1’s in the case of SHA256(?). Knowing the hash function’s internals in most cases does not make it less secure. Afaik, you can know the SHA256 internals and the outputs and will be none-the-wiser on the what the input was. Maybe some smart guy can figure out the pattern, but for some reason, it’s unreversible with current tools, pre-quantum era. The consistency of inputs always producing the same outputs, and with slightly different inputs changing the outputs, blockchain tech uses it to verify the blockchain.