diff --git a/captcha.module b/captcha.module
index 54d06f6..c3ebff9 100644
--- a/captcha.module
+++ b/captcha.module
@@ -216,12 +216,21 @@ function captcha_element_process($element, &$form_state, $complete_form) {
     '#value' => $captcha_sid,
   );
 
-  // Additional one time CAPTCHA token: store in database and send with form.
-  $captcha_token = md5(mt_rand());
-  db_update('captcha_sessions')
-    ->fields(array('token' => $captcha_token))
-    ->condition('csid', $captcha_sid)
-    ->execute();
+  $captcha_token = db_select('captcha_sessions', 'c')
+                      ->fields('c', array('token'))
+                      ->condition('csid', $captcha_sid)
+                      ->execute()
+                      ->fetchAssoc();
+  $captcha_token = $captcha_token['token'];
+  if (!isset($captcha_token) && !$form_state['submitted']) {
+  	    // Additional one time CAPTCHA token: store in database and send with form.
+  	    $captcha_token = md5(mt_rand());
+  	    db_update('captcha_sessions')
+  	      ->fields(array('token' => $captcha_token))
+  	      ->condition('csid', $captcha_sid)
+  	      ->execute();
+  	  }
+  
   $element['captcha_token'] = array(
     '#type' => 'hidden',
     '#value' => $captcha_token,
@@ -344,6 +353,9 @@ function captcha_form_alter(&$form, &$form_state, $form_id) {
       // Get placement in form and insert in form.
       $captcha_placement = _captcha_get_captcha_placement($form_id, $form);
       _captcha_insert_captcha_element($form, $captcha_placement, $captcha_element);
+      
+      // Add #submit functions to invalidate captcha
+      $form['#submit'][] = 'captcha_submit_invalidate_session';
     }
   }
   else if (
@@ -427,6 +439,20 @@ function captcha_form_alter(&$form, &$form_state, $form_id) {
 
 }
 
+/**
+ + * Invalidate CAPTCHA token to avoid reuse.
+ + * @param unknown_type $form
+ + * @param unknown_type $form_state
+ + */
+function captcha_submit_invalidate_session($form, $form_state) {
+	if (isset($form_state['captcha_info']['captcha_sid'])) {
+		db_update('captcha_sessions')
+			->fields(array('token' => NULL))
+			->condition('csid', $form_state['captcha_info']['captcha_sid'])
+		    ->execute();
+	}
+}
+
 /**
  * CAPTCHA validation function to tests strict equality.
  * @param $solution the solution of the test.
@@ -454,7 +480,7 @@ function captcha_validate_case_insensitive_equality($solution, $response) {
  * @return TRUE when equal (ignoring spaces), FALSE otherwise.
  */
 function captcha_validate_ignore_spaces($solution, $response) {
-  return preg_replace('/\s/', '', $solution) === preg_replace('/\s/', '', $response);
+  return preg_replace('/\s/', '', $solution) == preg_replace('/\s/', '', $response);
 }
 
 /**
@@ -464,7 +490,7 @@ function captcha_validate_ignore_spaces($solution, $response) {
  * @return TRUE when equal (ignoring spaces), FALSE otherwise.
  */
 function captcha_validate_case_insensitive_ignore_spaces($solution, $response) {
-  return preg_replace('/\s/', '', strtolower($solution)) === preg_replace('/\s/', '', strtolower($response));
+  return preg_replace('/\s/', '', strtolower($solution)) == preg_replace('/\s/', '', strtolower($response));
 }
 
 /**
@@ -533,10 +559,6 @@ function _captcha_get_posted_captcha_info($element, $form_state, $this_form_id)
           // Invalidate the CAPTCHA session.
           $posted_captcha_sid = NULL;
         }
-        // Invalidate CAPTCHA token to avoid reuse.
-        db_update('captcha_sessions')
-          ->fields(array('token' => NULL))
-          ->condition('csid', $posted_captcha_sid);
       }
     }
     else {