README

kelunik/two-factor is a Google Authenticator compatible OATH implementation.

Requirements

• PHP 5.5+

Installation

composer require kelunik/two-factor

Demo

There's a runnable demo contained in this repository.

Usage

Generate a secret per user

$oath = new Oath;

// this generates a key in binary format
$key = $oath->generateKey();

// store key for user

Let user setup two factor device

$oath = new Oath;
$key = "..."; // load user key from storage

// Use the URI to provide an easy to scan QR code
$uri = $oath->getUri($key);

// Alternatively display the key for manual input
$secret = $oath->encodeKey($key);

You can use your favourite JavaScript or PHP library to generate the QR code. For a working example, we're using qr.js.

<form action="/2fa/setup" method="POST">
    Scan the following QR code and click continue once you're ready.
    <input type="hidden" value="{{$uri}}" id="2fa-uri">

    <canvas id="qr-code"></canvas>
    <script src="/js/qr.min.js"></script>
    <script>
        qr.canvas({
            canvas: document.getElementById("qr-code"),
            value: document.getElementById("2fa-uri").value
        });
    </script>

    <button type="submit">Continue</button>
</form>

Validate TOTP value

$oath = new Oath;
$key = "..."; // load user key from storage
$isValid = $oath->verifyTotp($key, $totpValue);
// If the token is valid, ensure that it can't be used again.
// Because we use the default grace window size of two,
// we have to store the used TOTP value for at least 90 seconds,
// to prevent its usage explicitly.