md5 can't be calculated in reverse. Those so-called cracking only make a database by encrypting the password md5 and associating it with the original text one by one, so that the original text can be found out from those things. If it is not found, it means that it is a password that is difficult to crack. Generally, this kind of password contains symbols. Generally, the encryption operation starts with numbers, then adds letters, and finally adds symbols.