diff --git a/public/include/classes/user.class.php b/public/include/classes/user.class.php
index 53645025..4622874f 100644
--- a/public/include/classes/user.class.php
+++ b/public/include/classes/user.class.php
@@ -294,7 +294,7 @@ class User {
       $this->setErrorMessage( 'E-mail do not match' );
       return false;
     }
-    if (!is_numeric($pin) || strlen($pin) > 4) {
+    if (!is_numeric($pin) || strlen($pin) > 4 || strlen($pin) < 4) {
       $this->setErrorMessage( 'Invalid PIN' );
       return false;
     }
@@ -304,7 +304,7 @@ class User {
         VALUES (?, ?, ?, ?, ?)
           ");
     if ($this->checkStmt($stmt)) {
-      $stmt->bind_param('sssis', $username, hash("sha256", $password1.$this->salt), $email1, $pin, $apikey);
+      $stmt->bind_param('sssss', $username, hash("sha256", $password1.$this->salt), $email1, hash("sha256", $pin.$this->salt), $apikey);
       if (!$stmt->execute()) {
         $this->setErrorMessage( 'Unable to register' );
         if ($stmt->sqlstate == '23000') $this->setErrorMessage( 'Username already exists' );
diff --git a/sql/mmcfe_ng_structure.sql b/sql/mmcfe_ng_structure.sql
index 9d784de2..7a8d27da 100644
--- a/sql/mmcfe_ng_structure.sql
+++ b/sql/mmcfe_ng_structure.sql
@@ -3,7 +3,7 @@
 -- http://www.phpmyadmin.net
 --
 -- Host: localhost
--- Erstellungszeit: 12. Mai 2013 um 00:03
+-- Erstellungszeit: 12. Mai 2013 um 00:20
 -- Server Version: 5.5.31-0ubuntu0.13.04.1
 -- PHP-Version: 5.4.9-4ubuntu2
 
@@ -34,12 +34,13 @@ CREATE TABLE IF NOT EXISTS `accounts` (
   `email` varchar(255) DEFAULT NULL COMMENT 'Assocaited email: used for validating users, and re-setting passwords',
   `loggedIp` varchar(255) DEFAULT NULL,
   `sessionTimeoutStamp` int(255) DEFAULT NULL,
-  `pin` varchar(65) NOT NULL COMMENT 'four digit pin to allow account changes',
-  `api_key` varchar(65) DEFAULT NULL,
+  `pin` varchar(255) NOT NULL COMMENT 'four digit pin to allow account changes',
+  `api_key` varchar(255) DEFAULT NULL,
   `donate_percent` float DEFAULT '0',
   `ap_threshold` float DEFAULT '0',
   `coin_address` varchar(255) DEFAULT NULL,
-  PRIMARY KEY (`id`)
+  PRIMARY KEY (`id`),
+  UNIQUE KEY `username` (`username`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 -- --------------------------------------------------------