Brute-force vanity onion addresses.
curvy is a tool very similar mkp224o.
Keep in mind that this is probably not the best tool for this task, because it is written in a slow(er) language, as well as it ignoring the advice for searching for vanity addresses given in the specification.
$ curvy --prefix="foo" --output="./hs_ed25519_secret_key" --threads=64
public key: foob64oywfdxkr4mxxio4xis6lba2peoplvj64kqbpybd2n6sqq6joqd.onion
- Rewrite this in a language that natively supports threads and erases secret keys securely