security - How to make a password uncrackable for one username "System" -

i working on old website , trying make reach today's web standards. website contains many database tables on 1 million rows in of them. website not have user system: deleted user database table today. had 10k users, gone now. because of insecurity , way of information stored - yes ocd kicked in!), , making new table users , store passwords in right way! not using md5()! data added website before.. create user account called "system". default user show old data added website. how can make account inaccessible!? should putting password in database no 1 can crack (cracking should hard anyways because of password_hash() function)!

should put value shorter password_hash() function.. make account inaccessible on website? drawbacks of why should not this? or should make password complicated point won't remember it?

one last thing, consider answering before click button.

there few options:

1. add active column database

   you check column on login. way can have accounts still represented, not active (and hence can't authenticate them).

   if account you're ever doing with, may overkill.

2. empty password hash column

   then, when trying password_verify() against empty hash, fail.

   you could make random password, why bother?

   one note: sure make exception in password reset functionality not allow reset of system account.