# File lib_core/rucy/passwd.rb, line 48
    def add_encrypted_user(user, encrypted_password)
      if (! user || user.strip.empty?) then
        raise 'not allowd empty user'
      end
      if (! encrypted_password || encrypted_password.empty?) then
        raise 'not allowd empty password.'
      end
      @pw_db[user] = encrypted_password
      nil
    end