I am not a computer scientist, but would like to understand hashes such as SHA-256 more. Am I right in believing that a hash is simply a statement that a file produced a specific output (the hash), and that it does not contain the original file’s data in any way? Therefore, if someone had the hash of a file, the only way that they could recreate the original file, even with all the computing power in the world, would be to recreate files themselves randomly until they had one with the same hash?
Or more simply:
A hash is a unique serial number for a unique computer file. The serial number contains nothing about the file. The only way to know anything about the file is to recreate it independently through trial and error, where the hash offers nothing but confirmation that the created file matches the original.