Are there any best practices for implementing secure login scripts in PHP?

When implementing secure login scripts in PHP, it is important to follow best practices to prevent common security vulnerabilities such as SQL injection, cross-site scripting, and session hijacking. Some best practices include using parameterized queries to prevent SQL injection, validating user input to prevent cross-site scripting, and using secure hashing algorithms like bcrypt to store passwords securely. 

// Sample PHP code snippet for implementing secure login script

// Start session
session_start();

// Connect to database
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Validate user input
$username = htmlspecialchars($_POST['username']);
$password = $_POST['password'];

// Prepare SQL statement with parameterized query
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
$stmt->bindParam(':username', $username);
$stmt->execute();
$user = $stmt->fetch();

// Verify password using bcrypt
if ($user && password_verify($password, $user['password'])) {
    // Set session variables
    $_SESSION['user_id'] = $user['id'];
    $_SESSION['username'] = $user['username'];
    
    // Redirect to dashboard
    header('Location: dashboard.php');
    exit();
} else {
    // Display error message
    echo "Invalid username or password";
}

Keywords

password hashing session management CSRF protection SQL injection prevention secure cookie handling

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