So clearly the random garble in smspriv6fynj23u6.onion isn't recognizable enough for a user to spot a bogus one. And so as long as an adversary is willing to sp

So clearly the random garble in smspriv6fynj23u6.onion isn't recognizable enough for a user to spot a bogus one. And so as long as an adversary is willing to spend the same amount of money mining their bogus key as you are in generating the original, you're never going to win. My suggestion would be to, during the mining process, search the "random" portion of the domain for "recognizable strings" (probably just any dictionary words) and keep mining until a domain is found with a suitable level of "recognizability". This way you get the extra "strength" of having mined for a significantly longer string at only a fraction of the cost whilst an adversary would have to search for a much more specific string to mimic you convincingly. This is somewhat similar to facebook having "corewwwi" following their domain - not words they were specifically looking for I'm sure, but notable and so would be necessary to bruteforce. Consider it to be a bit like having "correcthorsebatterystaple" on the end of your domain (yeah I know it's too long).