build: documentation.

Author: LordDashMe

README.md

@@ -18,7 +18,111 @@ composer require lorddashme/php-two-factor-auth
 
 ## Usage
 
-- @TODO
+### HOTP
+
+- To generate HMAC-based One-Time Password algorithm:
+
+```php
+<?php
+
+require __DIR__  . '/vendor/autoload.php';
+
+use LordDashMe\TwoFactorAuth\RFC4226\HOTP;
+use LordDashMe\TwoFactorAuth\Utility\Base32;
+
+$hotp = new HOTP(Base32::encode('P@ssw0rd!'));
+$hotp->setLength(6)
+     ->prepare()
+     ->generate();
+
+echo $hotp->get(); // 444555
+```
+
+- To verify the generated HOTP:
+
+```php
+<?php
+
+require __DIR__  . '/vendor/autoload.php';
+
+use LordDashMe\TwoFactorAuth\RFC4226\HOTP;
+use LordDashMe\TwoFactorAuth\Utility\Base32;
+
+$hotp = new HOTP(Base32::encode('P@ssw0rd!'));
+$hotp->setLength(6)
+     ->prepare();
+
+echo $hotp->verify('444555'); // true
+```
+
+### TOTP
+
+- To generate Time-Based One-Time Password algorithm:
+
+```php
+<?php
+
+require __DIR__  . '/vendor/autoload.php';
+
+use LordDashMe\TwoFactorAuth\RFC6238\TOTP;
+use LordDashMe\TwoFactorAuth\Utility\Base32;
+
+$totp = new TOTP(Base32::encode('P@ssw0rd!'));
+$totp->setTimeRemainingInSeconds(30)
+     ->setTimeAdjustments(10)
+     ->setLength(6)
+     ->prepare()
+     ->generate();
+
+echo $totp->get(); // 552344
+```
+
+- To verify the generated TOTP:
+
+```php
+<?php
+
+require __DIR__  . '/vendor/autoload.php';
+
+use LordDashMe\TwoFactorAuth\RFC6238\TOTP;
+use LordDashMe\TwoFactorAuth\Utility\Base32;
+
+$totp = new TOTP(Base32::encode('P@ssw0rd!'));
+$totp->setTimeRemainingInSeconds(30)
+     ->setTimeAdjustments(10)
+     ->setLength(6)
+     ->prepare();
+
+echo $totp->verify('552344'); // true
+```
+
+### Google Authenticator Barcode Generation
+
+- To generate a barcode image that will use by the Google Authenticator mobile app:
+
+```php
+<?php
+
+require __DIR__  . '/vendor/autoload.php';
+
+use LordDashMe\TwoFactorAuth\Utility\Base32;
+use LordDashMe\TwoFactorAuth\GoogleAuthenticator\BarcodeURL;
+use LordDashMe\TwoFactorAuth\GoogleAuthenticator\TOTPFormat;
+
+$secret = Base32::encode('P@ssw0rd!', false);
+$accountUser = 'reyesjoshuaclifford@gmail.com';
+$issuer = 'TwoFactorAuth';
+$digits = 6;
+$period = 30;
+
+$totpFormat = new TOTPFormat($period);
+$barcodeURL = new BarcodeURL($secret, $accountUser, $issuer, $totpFormat);
+$barcodeURL->setAlgorithm('SHA1')
+           ->setDigits($digits)
+           ->build();
+
+echo $barcodeURL->get(); // https://chart.googleapis.com/chart?chs=200x200&chld=M|0&cht=qr&chl=otpauth://totp/TwoFactorAuth:reyesjoshuaclifford@gmail.com?secret=KBAHG43XGBZGIII&algorithm=SHA1&digits=6&period=30&issuer=TwoFactorAuth
+```
 
 ## Other Reference