there was a giveaway in the past that was solved.
the solution was a url found on a message from the transaction. but the url was a locked .txt document that needed a password to unlock.
i can't find the site that was used in that giveaway or even the thread. so i cant try it.

i don't think bruteforcing will work esp if it needs to be converted to the private key, but i have seen alot of theories once you get past the first 3-4 pages