PHP验证（）。如何验证哈希传递？

Question

此授权代码页。 MySQL数据库密码使用＆＃34; password_hash＆＃34;。

加密

我知道这里有必要规定＆＃34; password_verify＆＃34;但我无法理解。

此代码：

session_start();
if(isset($_REQUEST['login_button'])||$_REQUEST['auto']==1){
    require '../_database/database.php';
    $errmsg_arr = array();
    $errflag = false;
    $user_username=   mysqli_real_escape_string($database,$_REQUEST['user_username']);
    $user_password=  mysqli_real_escape_string($database,$_REQUEST['user_password']);
    if($user_username == '') {
        $errmsg_arr[] = 'BOO! WHERE LOGIN?';
        $errflag = true;
    }
    if($user_password == '') {
        $errmsg_arr[] = 'BOO! WHERE Password?';
        $errflag = true;
    }
    if($errflag) {
        $_SESSION['ERRMSG_ARR'] = $errmsg_arr;
        session_write_close();
        header("location: authentication-check.php");
        exit();
    }
    $sql="SELECT user_username,user_password FROM user WHERE user_username='$user_username'AND user_password='$user_password'";
    $result=  mysqli_query($database,$sql) or die(mysqli_errno());
    $trws= mysqli_num_rows($result);
    if($trws==1){
        $rws=  mysqli_fetch_array($result);
        $_SESSION['user_username']=$rws['user_username'];
        $_SESSION['user_password']=$rws['user_password'];
        header("location:../home.php?user_username=$user_username&request=login&status=success");    
    }
    else {
        $errmsg_arr[] = 'USERNAME OR PASSWORD INCORRECT, RECHECK NOW';
        $errflag = true;
        if($errflag) {
            $_SESSION['ERRMSG_ARR'] = $errmsg_arr;
            session_write_close();
            header("location: ../components/authentication-check.php");
            exit();
        }
    }
}