The best alternative for you is GnuPG or BCArchive.
Both are free and open source.
Or, as I said earlier, you can use AxCrypt 2 in permanently offline mode. Turn off your network connection, enter a fake email and then activate permanently offline. Job done.
But you can’t use AES-256 in free AxCrypt and premium requires an initial network connection.
BCArchive is free and allows you to choose your cipher, hash and iteration count.