And for those who still think that a hashing function is reversible, let me give you a quick rundown on why that's practically impossible.

A hashing function like SHA256 or RIPEMD160 or MD5 aren't encryption functions, meaning they are NOT meant to "hide" data so only someone with the correct keys could read it. They are only used for VERIFICATION, meaning they don't hold ANY information on the underlying data, but are simply used to represent a unique signature associated with that specific piece of data to detect alterations or tampering.

What makes them irreversible is that they completely disregard some parts of the data through the use of bit-shifting and mixing different keys. Take a modular function for example, N = m (mod k),  m still hold a piece of information related to N, but you can't recover N knowing m and k. Now combine that with conditional operations, boolean operations and so one, for 64 rounds. And there you have it, a 256bit string that just tells you the file or message is what it's claiming to be.

Focus your efforts on more software or hardware optimizations instead of wasting your time on mathematical paradoxes. That's the whole point of this challenge, to push creativity and ingenuity to its limits, not foster insanity and delusion.