You can look it up in a Japanese dictionary. If you’re using iOS devices, you can download one.
If you want to input a kannji,you can using a Chinese handwriting input.
If you are talking about the kanji name in the animes maybe the only way is to listen it in the animation or refer from their HP.
Actually,there is no efficient and workable password cracker. If you’re really going to use one,you might have to wait for a really long time since our PCs are often not fast enough to finish such a calculation in a relatively short time.