diff --git a/field.class.php b/field.class.php
index f761b96..7932001 100644
--- a/field.class.php
+++ b/field.class.php
@@ -1,38 +1,23 @@
 <?php
 
 class profile_field_cpf extends profile_field_base {
-
     /**
      * Overwrite the base class to display the data for this field
      */
     function display_data() {
         /// Default formatting
         $data = parent::display_data();
+        $data = str_pad($data, 11, '0', STR_PAD_LEFT); // Prevent low digits formatting errors
         if ($data !== '') {
             $data = substr($data,0,3).'.'.substr($data,3,3).'.'.substr($data,6,3).'-'.substr($data,9,2);
         }
-/*
-        /// Are we creating a link?
-        if (!empty($this->field->param4) and !empty($data)) {
-
-            /// Define the target
-            if (! empty($this->field->param5)) {
-                $target = 'target="'.$this->field->param5.'"';
-            } else {
-                $target = '';
-            }
-
-            /// Create the link
-            $data = '<a href="'.str_replace('$$', urlencode($data), $this->field->param4).'" '.$target.'>'.htmlspecialchars($data).'</a>';
-        }
-*/
         return $data;
     }
 
     function edit_field_add($mform) {
         /// Create the form field
         $mform->addElement('text', $this->inputname, format_string($this->field->name), 'maxlength="11" size="11"');
-        $mform->setType($this->inputname, PARAM_INT);
+        $mform->setType($this->inputname, PARAM_TEXT);
     }
 
     function edit_validate_field($usernew) {
@@ -40,6 +25,9 @@ class profile_field_cpf extends profile_field_base {
         $errors = array();
         if (isset($usernew->{$this->inputname})) {
             $cpf = $usernew->{$this->inputname};
+            if (ctype_digit($cpf)) {
+                return array($this->inputname => get_string('cpf_digits', 'profilefield_cpf'));
+            }
             if (strlen($cpf) != 11) {
                 return array($this->inputname => get_string('cpf_size', 'profilefield_cpf'));
             }
@@ -62,5 +50,3 @@ class profile_field_cpf extends profile_field_base {
     }
 
 }
-
-
diff --git a/lang/en/profilefield_cpf.php b/lang/en/profilefield_cpf.php
index 155f114..73853af 100644
--- a/lang/en/profilefield_cpf.php
+++ b/lang/en/profilefield_cpf.php
@@ -24,5 +24,6 @@
  */
 
 $string['pluginname'] = 'Brazilian CPF';
+$string['cpf_digits'] = 'CPF must have only numeric digits';
 $string['cpf_size'] = 'CPF must have 11 digits';
 $string['cpf_invalid'] = 'Invalid CPF';