diff --git a/PHPGangsta/GoogleAuthenticator.php b/PHPGangsta/GoogleAuthenticator.php
index bf7d116..487f07f 100644
--- a/PHPGangsta/GoogleAuthenticator.php
+++ b/PHPGangsta/GoogleAuthenticator.php
@@ -53,25 +53,30 @@ public function createSecret($secretLength = 16)
     }
 
     /**
-     * Calculate the code, with given secret and point in time.
+     * Calculate the code, with given secret, point in time and
+     * hmac algorithm.
      *
-     * @param string   $secret
-     * @param int|null $timeSlice
+     * @param string       $secret
+     * @param int|null     $timeSlice
+     * @param string|null  $algo
      *
      * @return string
      */
-    public function getCode($secret, $timeSlice = null)
+    public function getCode($secret, $timeSlice = null, $algo = null)
     {
         if ($timeSlice === null) {
             $timeSlice = floor(time() / 30);
         }
+        if ($algo === null) {
+            $algo = 'SHA1';
+        }
 
         $secretkey = $this->_base32Decode($secret);
 
         // Pack time into binary string
         $time = chr(0).chr(0).chr(0).chr(0).pack('N*', $timeSlice);
         // Hash it with users secret key
-        $hm = hash_hmac('SHA1', $time, $secretkey, true);
+        $hm = hash_hmac($algo, $time, $secretkey, true);
         // Use last nipple of result as index/offset
         $offset = ord(substr($hm, -1)) & 0x0F;
         // grab 4 bytes of the result
@@ -103,8 +108,9 @@ public function getQRCodeGoogleUrl($name, $secret, $title = null, $params = arra
         $width = !empty($params['width']) && (int) $params['width'] > 0 ? (int) $params['width'] : 200;
         $height = !empty($params['height']) && (int) $params['height'] > 0 ? (int) $params['height'] : 200;
         $level = !empty($params['level']) && array_search($params['level'], array('L', 'M', 'Q', 'H')) !== false ? $params['level'] : 'M';
+        $algo = !empty($params['algo']) ? strtoupper($params['algo']) : 'SHA1';
 
-        $urlencoded = urlencode('otpauth://totp/'.$name.'?secret='.$secret.'');
+        $urlencoded = urlencode('otpauth://totp/'.$name.'?secret='.$secret.($algo != 'SHA1' ? '&algorithm='.$algo : ''));
         if (isset($title)) {
             $urlencoded .= urlencode('&issuer='.urlencode($title));
         }
@@ -115,25 +121,26 @@ public function getQRCodeGoogleUrl($name, $secret, $title = null, $params = arra
     /**
      * Check if the code is correct. This will accept codes starting from $discrepancy*30sec ago to $discrepancy*30sec from now.
      *
-     * @param string   $secret
-     * @param string   $code
-     * @param int      $discrepancy      This is the allowed time drift in 30 second units (8 means 4 minutes before or after)
-     * @param int|null $currentTimeSlice time slice if we want use other that time()
+     * @param string      $secret
+     * @param string      $code
+     * @param int         $discrepancy      This is the allowed time drift in 30 second units (8 means 4 minutes before or after)
+     * @param int|null    $currentTimeSlice time slice if we want use other that time()
+     * @param string|null $algo             Algorithm to use to validate code with.
      *
      * @return bool
      */
-    public function verifyCode($secret, $code, $discrepancy = 1, $currentTimeSlice = null)
+    public function verifyCode($secret, $code, $discrepancy = 1, $currentTimeSlice = null, $algo = null)
     {
         if ($currentTimeSlice === null) {
             $currentTimeSlice = floor(time() / 30);
         }
 
-        if (strlen($code) != 6) {
+        if (strlen($code) != $this->_codeLength) {
             return false;
         }
 
         for ($i = -$discrepancy; $i <= $discrepancy; ++$i) {
-            $calculatedCode = $this->getCode($secret, $currentTimeSlice + $i);
+            $calculatedCode = $this->getCode($secret, $currentTimeSlice + $i, $algo);
             if ($this->timingSafeEquals($calculatedCode, $code)) {
                 return true;
             }
diff --git a/tests/GoogleAuthenticatorTest.php b/tests/GoogleAuthenticatorTest.php
index 4e13b5c..240b5b3 100644
--- a/tests/GoogleAuthenticatorTest.php
+++ b/tests/GoogleAuthenticatorTest.php
@@ -2,6 +2,12 @@
 
 require_once __DIR__.'/../vendor/autoload.php';
 
+if (!class_exists('PHPUnit_Framework_TestCase') && class_exists('\PHPUnit\Framework\TestCase')) {
+    class PHPUnit_Framework_TestCase extends \PHPUnit\Framework\TestCase
+    {
+    }
+}
+
 class GoogleAuthenticatorTest extends PHPUnit_Framework_TestCase
 {
     /* @var $googleAuthenticator PHPGangsta_GoogleAuthenticator */
@@ -14,11 +20,32 @@ protected function setUp()
 
     public function codeProvider()
     {
-        // Secret, time, code
+        // Secret, timeSlice, code, codeLength, algo
         return array(
             array('SECRET', '0', '200470'),
             array('SECRET', '1385909245', '780018'),
             array('SECRET', '1378934578', '705013'),
+
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ', '1', '94287082', 8, 'SHA1'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ', '37037036', '07081804', 8, 'SHA1'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ', '37037037', '14050471', 8, 'SHA1'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ', '41152263', '89005924', 8, 'SHA1'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ', '66666666', '69279037', 8, 'SHA1'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ', '666666666', '65353130', 8, 'SHA1'),
+
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA', '1', '46119246', 8, 'SHA256'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA', '37037036', '68084774', 8, 'SHA256'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA', '37037037', '67062674', 8, 'SHA256'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA', '41152263', '91819424', 8, 'SHA256'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA', '66666666', '90698825', 8, 'SHA256'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA', '666666666', '77737706', 8, 'SHA256'),
+
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA', '1', '90693936', 8, 'SHA512'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA', '37037036', '25091201', 8, 'SHA512'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA', '37037037', '99943326', 8, 'SHA512'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA', '41152263', '93441116', 8, 'SHA512'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA', '66666666', '38618901', 8, 'SHA512'),
+            array('GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA', '666666666', '47863826', 8, 'SHA512'),
         );
     }
 
@@ -51,9 +78,10 @@ public function testCreateSecretLengthCanBeSpecified()
     /**
      * @dataProvider codeProvider
      */
-    public function testGetCodeReturnsCorrectValues($secret, $timeSlice, $code)
+    public function testGetCodeReturnsCorrectValues($secret, $timeSlice, $code, $length = 6, $algo = 'SHA1')
     {
-        $generatedCode = $this->googleAuthenticator->getCode($secret, $timeSlice);
+        $this->googleAuthenticator->setCodeLength($length);
+        $generatedCode = $this->googleAuthenticator->getCode($secret, $timeSlice, $algo);
 
         $this->assertEquals($code, $generatedCode);
     }
@@ -108,4 +136,11 @@ public function testSetCodeLength()
 
         $this->assertInstanceOf('PHPGangsta_GoogleAuthenticator', $result);
     }
+
+    public function testValidateCorrectCodeLength()
+    {
+        $secret = 'SECRET';
+        $this->googleAuthenticator->setCodeLength(8);
+        $this->assertEquals(true, $this->googleAuthenticator->verifyCode($secret, $this->googleAuthenticator->getCode($secret)));
+    }
 }