Přihlašovací formulář - Přihlašování za použití hesel SHA1

<!-- LOGIN FORM in: admin/index.php -->
<form method="post" action="#">
    <p><label for="u_name">username:</label></p>
    <p><input type="text" name="u_name" value=""></p>
    
    <p><label for="u_pass">password:</label></p>
    <p><input type="password" name="u_pass" value=""></p>
    
    <p><button type="submit" name="go">log me in</button></p>
</form>
<!-- A paragraph to display eventual errors -->
<p><strong><?php if(isset($error)){echo $error;}  ?></strong></p> 


<?php #admin/index.php 
           #####[make sure you put this code before any html output]#####

//connect to server

   
$dbc = mysqli_connect('db.com','','') or 
           die('could not connect: '. mysqli_connect_error());

//select db
mysqli_select_db($dbc, '') or die('no db connection');

//check if the login form has been submitted
if(isset($_POST['go'])){
    #####form submitted, check data...#####
    
        //step 1a: sanitise and store data into vars (storing encrypted password)
    $usr = mysqli_real_escape_string($dbc, htmlentities($_POST['u_name']));
    $psw = SHA1($_POST['u_pass']) ; //using SHA1() to encrypt passwords  
     
        //step2: create query to check if username and password match
    $q = "SELECT * FROM authme WHERE username='$usr' AND password='$psw'  ";
    
    //step3: run the query and store result
    $res = mysqli_query($dbc, $q);

    //make sure we have a positive result
    if(mysqli_num_rows($res) == 1){
        #########  LOGGING IN  ##########
        //starting a session  
                session_start();

                //creating a log SESSION VARIABLE that will persist through pages   
        $_SESSION['log'] = 'in';

        //redirecting to restricted page
        header('location:detail.php');
    } else {
                //create an error message   
        $error = 'Wrong details. Please try again';    
    }
}//end isset go
?> 
<!-- HTML FORM GOES HERE -->