Added TOTP Key 2FA Function to client logins

functions.php

@@ -218,4 +218,40 @@ function get_currency_symbol($cc = 'USD')
     }
 }
 
+function get_otp($secret_seed) {
+    //TOTP seed (String representation)
+    $otp = '';
+    //number of seconds of otp period
+    $time_window = 30;
+
+    //time formating to epoch
+    $exact_time = microtime(true);
+    $rounded_time = floor($exact_time/$time_window);
+
+    //binary represetation of time without padding
+    $packed_time = pack("N", $rounded_time);
+
+    //binary representation of time with padding
+    $padded_packed_time = str_pad($packed_time,8, chr(0), STR_PAD_LEFT);
+
+    //binary representation of seed
+    $packed_secret_seed = pack("H*", $secret_seed);
+
+    //HMAC SHA1 hash (time + seed)
+    $hash = hash_hmac ('sha1', $padded_packed_time, $packed_secret_seed, true);
+
+    $offset = ord($hash[19]) & 0xf;
+    $otp = (
+            ((ord($hash[$offset+0]) & 0x7f) << 24 ) |
+            ((ord($hash[$offset+1]) & 0xff) << 16 ) |
+            ((ord($hash[$offset+2]) & 0xff) << 8 ) |
+            (ord($hash[$offset+3]) & 0xff)
+    ) % pow(10, 6); 
+
+    //adding pad to otp, in order to assure a "6" digits
+    $otp = str_pad($otp, 6, "0", STR_PAD_LEFT);
+
+    return $otp;
+}
+
 ?>