I know it's almost impossible to do, SHA256 is a one-way function that can't be easily reversed, just like there are operations that have no reverse, take: $f(x) = x+5$ , it's easy to see that if you want to revert that you just take the output and subtract 5, you'll get the original input, the reverse would then be $f(y) = y-5$ For $f(x) = 7, there's nothing you can do about it, no matter what X is, you always get 7, you can easily input any X, get the output, and get 7, but to gt the original input, there are infinite possibilities.
Similarly, sha256 can't be unhashed because of this, mod operator has no inverse, for example, yet, there are ways around that, what I mean is, 22%7 is 1, 7 ? 1 = 22, no operator for that, but I can take a set of numbers that when moded with 7, x%7 = 1, this is still infinite, but this infinite is smaller than all N numbers.
So, would it be possible to try to unhash a sha256 making a list of "candidates" or finding some rules about the seed that leads to that hash?
When I was thinking about this, I found this really interesting research on Github
I'm a newcomer in this world, but now I feel very interested in ways to unhash a sha256 other than brute-forcing which is not unhashing, is just hashing everything until a match. What other ways are known that are not brute-forcing? Is really that the only approach there is?