Current Location: Home> Latest Articles> Complete Guide to Implementing Secure User Authentication with OpenID Connect in PHP

Complete Guide to Implementing Secure User Authentication with OpenID Connect in PHP

M66 2025-07-23

Understanding OpenID Connect

OpenID Connect is an authentication and authorization protocol built on top of OAuth 2.0. It allows users to log in using credentials from third-party providers such as Google or Facebook. This protocol offers developers a standardized and secure way to verify user identities and implement seamless login experiences within their applications.

Implementing Secure Authentication with OpenID Connect in PHP

Installing and Configuring Required Components

Before starting development, ensure that your server environment has PHP installed along with common extensions such as OpenSSL, cURL, and JSON support. If not installed, you can install them using the following command:

$ sudo apt-get install php openssl php-curl php-json

Creating an OpenID Connect Client

First, register a client application in the OpenID provider’s developer console. During registration, provide a unique Client ID and Client Secret, and configure a redirect URL where users will be sent after successful authentication.

PHP Code for Secure Authentication

Include the necessary PHP libraries:

require_once 'vendor/autoload.php';
use OpenIDConnectClient;

Create a client instance and set parameters:

$clientID = 'your-client-id';
$clientSecret = 'your-client-secret';
$redirectURL = 'your-redirect-url';
$oidc = new OpenIDConnectClient($clientID, $clientSecret);
$oidc->setRedirectURL($redirectURL);
$oidc->setProviderURL('https://your-openid-provider.com');

Initiate the authentication request and handle the callback:

if (!isset($_GET['code'])) {
    // User is not authenticated yet, redirect to authentication page
    $authorizationURL = $oidc->getAuthorizationURL();
    header('Location: ' . $authorizationURL);
    exit;
} else {
    // User has authenticated, exchange authorization code for access token
    $code = $_GET['code'];
    $oidc->authenticate($code);
    $accessToken = $oidc->getAccessToken();
    $userInfo = $oidc->requestUserInfo();
    
    // You can handle user login or other logic here
}

Summary

Using OpenID Connect, PHP applications can implement secure and standardized user authentication. By registering a client with an OpenID provider and following a straightforward code flow, you can authenticate users and retrieve their information securely. This approach greatly improves application security and user experience, eliminates the risks of handling passwords directly, and supports multiple popular identity providers, making it suitable for various PHP projects.

Related