Login.php (controller)

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Login extends CI_Controller
{

    function __construct()
    {
        parent::__construct();
        $this->load->model('admin'); //load model admin
    }

    public function index()
    {
        //membuat password untuk admin yang te;ah di encrypsi
        // echo password_hash('admin', PASSWORD_DEFAULT, ['cost' => 10]);

        //proses autentikasi
        if ($this->input->post('submit') == 'Submit' )
        {
            //variabelvariabel untuk menerima value yang dikirim form inputnya
            $user = $this->input->post('username', TRUE);
            $pass = $this->input->post('password', TRUE);

            //variabel untuk pengecekan
            $cek = $this->admin->get_where('t_admin', array('username' => $user));

            //jika proses verivikasi pada username sudah berjalan maka lakukan verivikasi pada password
            if ($cek->num_rows() > 0)
            {
                $data = $cek->row();

                if (password_verify($pass, $data->password))
                {
                    //session
                    $datauser = array
                    (
                        'user' => $data->fullname,
                        'level' => $data->level,
                        'login' => TRUE
                    );

                    $this->session->set_userdata($datauser);

                    redirect ('index.php/admin');
                }

                else
                {
                    echo '<p style="color:white">Password Salah</p>';
                }
            }

            else
            {
                echo '<p style="color:white">Gagal</p>';
            }
        }

        $this->load->view('admin/login_form');
    }
}