How can PHP developers ensure data integrity and prevent manipulation of cookies by users?

To ensure data integrity and prevent manipulation of cookies by users, PHP developers can encrypt the cookie data before setting it and decrypt it when retrieving it. This way, even if a user tries to modify the cookie value, they won't be able to read or change the actual data stored in it. 

// Encrypt cookie data before setting it
$cookieValue = 'sensitive_data';
$encryptedValue = openssl_encrypt($cookieValue, 'AES-256-CBC', 'secret_key', 0, '16charIV');
setcookie('cookie_name', $encryptedValue, time() + 3600, '/');

// Decrypt cookie data when retrieving it
if(isset($_COOKIE['cookie_name'])){
    $decryptedValue = openssl_decrypt($_COOKIE['cookie_name'], 'AES-256-CBC', 'secret_key', 0, '16charIV');
    echo $decryptedValue;
}

Related Questions