### Instantiate Google2FA Directly

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Instantiate the Google2FA class directly to begin using its features. This is the primary way to get started with the package.

```php
use PragmaRX\Google2FA\Google2FA;

$google2fa = new Google2FA();

return $google2fa->generateSecretKey();
```

--------------------------------

### Run PHPUnit Tests

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Execute the package's tests using Composer and PHPUnit. Ensure Composer is installed and the package dependencies are managed.

```bash
composer test
```

--------------------------------

### Set OTP Window for Verification

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Verifies a key using a specified window size. A window of 0 means the OTP is valid for 30 seconds, while a window of 2 makes it valid for 120 seconds.

```php
$isValid = $google2fa->verifyKey($seed, $key, 4);
```

--------------------------------

### Render QR Code with Simple QrCode

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Renders a QR code using the Simple QrCode package, suitable for printing.

```php
<div class="visible-print text-center">
    {!! QrCode::size(100)->generate($google2fa->getQRCodeUrl($companyName, $companyEmail, $secretKey)); !!}
    <p>Scan me to return to the original page.</p>
</div>
```

--------------------------------

### Generate QR Code Image with Bacon/QRCode

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates a QR code image using Bacon/QRCode and encodes it as a base64 string for display.

```php
<?php

use PragmaRX\Google2FA\Google2FA;
use BaconQrCode\Renderer\ImageRenderer;
use BaconQrCode\Renderer\Image\ImagickImageBackEnd;
use BaconQrCode\Renderer\RendererStyle\RendererStyle;
use BaconQrCode\Writer;

$google2fa = app(Google2FA::class);

$g2faUrl = $google2fa->getQRCodeUrl(
    'pragmarx',
    'google2fa@pragmarx.com',
    $google2fa->generateSecretKey()
);

$writer = new Writer(
    new ImageRenderer(
        new RendererStyle(400),
        new ImagickImageBackEnd()
    )
);

$qrcode_image = base64_encode($writer->writeString($g2faUrl));
?>
```

--------------------------------

### Verify Google Authenticator Key with Window

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Validates a provided key against the user's secret, considering a window of past and future keys to account for clock drift. Defaults to a window of 1.

```php
$secret = $request->input('secret');

$window = 8; // 8 keys (respectively 4 minutes) past and future

$valid = $google2fa->verifyKey($user->google2fa_secret, $secret, $window);
```

--------------------------------

### Set OTP Window Globally

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Sets the window property for OTP validity. This determines how many 30-second cycles an OTP will be considered valid.

```php
$secretKey = $google2fa->setWindow(4);
```

--------------------------------

### Display QR Code Data URI with Endroid

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Displays a QR code generated as a data URI in an HTML view.

```php
<div class="visible-print text-center">
    {!! $google2fa_url !!}
    <p>Scan me to return to the original page.</p>
</div>
```

--------------------------------

### Generate Secret Key with Prefix

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates a secret key with a specified prefix. The prefix length must be compatible with base 32 conversion and the secret key's power-of-2 length.

```php
$prefix = strpad($userId, 10, 'X');

$secretKey = $google2fa->generateSecretKey(16, $prefix);
```

--------------------------------

### Original GPLv3 License Text

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/RELICENSED.md

This block contains the full text of the GNU General Public License v3, under which the Google2FA package was originally licensed. It outlines the terms for redistribution and modification.

```php
/**
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * PHP Google two-factor authentication module.
 *
 * See https://www.idontplaydarts.com/2011/07/google-totp-two-factor-authentication-for-php/
 * for more details
 *
 * @author Phil
 **/
```

--------------------------------

### Generate QR Code Data URI with Endroid

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates a data URI for a QR code using the Endroid QR Code library.

```php
$qrCode = new \Endroid\QrCode\QrCode($value);
$qrCode->setSize(100);
$google2fa_url = $qrCode->writeDataUri();
```

--------------------------------

### Perform PHPStan Analysis

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Run static analysis on the codebase using PHPStan via Composer. This helps identify potential code quality issues.

```bash
composer analyse
```

--------------------------------

### Pad Secret Key for Google Authenticator Compatibility

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Use this to pad a secret key to the nearest power of 2 length (8, 16, 32, etc.) to ensure compatibility with Google Authenticator. The padding character 'X' is used here.

```php
$secretKey = '123456789';

$secretKey = str_pad($secretKey, pow(2,ceil(log(strlen($secretKey),2))), 'X');
```

--------------------------------

### Generate 16-character secret key (v8.x and below)

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

This snippet shows how to generate a 16-character secret key, replicating the default behavior of versions prior to 9.0.0.

```php
$secret = $google2fa->generateSecretKey();
```

--------------------------------

### Verify Google Authenticator Key (Newer)

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Verifies a key and ensures it has not been used before by checking against the last used timestamp. Updates the timestamp upon successful validation.

```php
$secret = $request->input('secret');

$timestamp = $google2fa->verifyKeyNewer($user->google2fa_secret, $secret, $user->google2fa_ts);

if ($timestamp !== false) {
    $user->update(['google2fa_ts' => $timestamp]);
    // successful
} else {
    // failed
}
```

--------------------------------

### Display Base64 Encoded QR Code Image

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Displays a QR code image that has been encoded as a base64 string.

```php
<img src="data:image/png;base64, <?php echo $qrcode_image; ?> "/>
```

--------------------------------

### Generate Data URL for QR Code

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates a data URL for a QR code using a custom function, suitable for embedding in HTML.

```php
// Use your own QR Code generator to generate a data URL:
$google2fa_url = custom_generate_qrcode_url($qrCodeUrl);

/// and in your view:

<img src="{{ $google2fa_url }}" alt="">
```

--------------------------------

### Generate Secret Key for User

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generate a secret key for a user and store it. The default length is 32 characters, but you can specify 16 characters for compatibility.

```php
// Generates a 32-character secret key (v9.0.0+ default)
$user->google2fa_secret = $google2fa->generateSecretKey();
```

```php
// Or explicitly specify 16 characters for compatibility
$user->google2fa_secret = $google2fa->generateSecretKey(16);
```

--------------------------------

### Generate QR Code URL

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates the URL for a QR code that can be used with any QR code generator library.

```php
$qrCodeUrl = $google2fa->getQRCodeUrl(
    $companyName,
    $companyEmail,
    $secretKey
);
```

--------------------------------

### Generate Inline QR Code

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates a QR code directly as an inline data URI for immediate use in an HTML image tag.

```php
$google2fa = (new \PragmaRX\Google2FAQRCode\Google2FA());

$inlineUrl = $google2fa->getQRCodeInline(
    'Company Name',
    'company@email.com',
    $google2fa->generateSecretKey()
);
```

--------------------------------

### Set HMAC Algorithm

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Use `setAlgorithm()` to specify SHA256 or SHA512 for enhanced security. Defaults to SHA1.

```php
use PragmaRX\Google2FA\Support\Constants;

$google2fa->setAlgorithm(Constants::SHA512);
```

--------------------------------

### Set Key Regeneration Interval

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Changes the key regeneration interval, which defaults to 30 seconds. Modifying this may cause sync issues with standard authenticator apps.

```php
$google2fa->setKeyRegeneration(40);
```

--------------------------------

### Generate 16-character secret key (v9.0+)

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

This snippet demonstrates how to explicitly generate a 16-character secret key in versions 9.0.0 and above, maintaining compatibility with older defaults.

```php
$secret = $google2fa->generateSecretKey(16);
```

--------------------------------

### Verify Google Authenticator Code

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Verifies a user-provided 2FA code against their stored secret key.

```php
$secret = $request->input('secret');

$valid = $google2fa->verifyKey($user->google2fa_secret, $secret);
```

--------------------------------

### Generate Secret Key with Specific Length

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Generates a secret key. Use 32 bytes for the default behavior in v9.0.0+ or 16 bytes for v8.x behavior.

```php
$secretKey = $google2fa->generateSecretKey(32); // now defaults to 32 bytes (v9.0.0+)
$secretKey = $google2fa->generateSecretKey(16); // for 16 byte keys (v8.x behavior)
```

--------------------------------

### Disable Google Authenticator Compatibility Enforcement

Source: https://github.com/antonioribeiro/google2fa/blob/9.x/README.md

Call this method to disable the package's default enforcement of Google Authenticator secret key compatibility if it's not a target requirement.

```php
$google2fa->setEnforceGoogleAuthenticatorCompatibility(false);
```

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