6226f7cbe59e99a90b5cef6f94f966fd

I should also think about possible errors. Could "6226f7cbe59e99a90b5cef6f94f966fd" have a typo? Let me count the characters: 6226f... it's 32 characters, which is correct for SHA-256. So that's a SHA-256 hash. Without the original document, I can't retrieve the paper from the hash alone.