php dev101

ASASA — Tue, 21 Apr 2026 19:56:00 +0000

Secure PHP Authentication System (PDO + MySQL)

Hey everyone (:

In this project, I built a secure authentication system using PHP and MySQL with PDO.
The goal was to understand how login systems work and how to make them more secure.

Project Idea

This application allows users to:

Register an account
Login securely
Access a protected dashboard
Logout

Database (phpMyAdmin)

This is the users table in phpMyAdmin.

It contains:

id → primary key
name → user name
user_email → email address
password → hashed password
birthdate→ birthdate

Passwords are stored using hashing for security.

Database Connection (PDO)

<?php
$host = "localhost";
$dbname = "sport_db";
$username = "root";
$password = "";

try {
    $pdo = new PDO("mysql:host=$host;dbname=$dbname;charset=utf8", $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
    die("Connection failed: " . $e->getMessage());
}
?>

Registration System

<?php
require "config/database.php";

if ($_SERVER["REQUEST_METHOD"] === "POST") {

    $name = trim($_POST['name']);
    $email = trim($_POST['email']);
    $password = password_hash($_POST['password'], PASSWORD_BCRYPT);

    $sql = "INSERT INTO users (name, user_email, password) VALUES (:name, :email, :password)";
    $stmt = $pdo->prepare($sql);

    $stmt->execute([
        ':name' => $name,
        ':email' => $email,
        ':password' => $password
    ]);

    echo "Registration successful!";
}
?>

Login System

<?php
session_start();
require "config/database.php";

if ($_SERVER["REQUEST_METHOD"] === "POST") {

    $email = $_POST['email'];
    $password = $_POST['password'];

    $sql = "SELECT * FROM users WHERE user_email = :email";
    $stmt = $pdo->prepare($sql);
    $stmt->execute([':email' => $email]);

    $user = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($user && password_verify($password, $user['password'])) {

        $_SESSION['user_id'] = $user['id'];
        $_SESSION['name'] = $user['name'];

        header("Location: dashboard.php");
        exit;

    } else {
        echo "Invalid credentials!";
    }
}
?>

Dashboard (Protected Page)

<?php
session_start();

if (!isset($_SESSION['user_id'])) {
    header("Location: login.php");
    exit;
}
?>

<h1>Welcome <?php echo $_SESSION['name']; ?></h1>

Logout

<?php
session_start();
session_destroy();

header("Location: login.php");
exit;
?>

Security Features

Password hashing using bcrypt
Secure queries with PDO prepared statements
Session-based authentication
Protection against SQL Injection

What I Learned

Building a secure authentication system
Using PDO in PHP
Managing sessions
Structuring a real web project

Future Improvements

Add form validation
Improve UI
Add password reset
Add user profile

Conclusion

This project helped me understand how authentication systems work in real applications and how to make them more secure.

Feedback is welcome!

DEV Community: ASASA