diff --git a/Type/CaptchaType.php b/Type/CaptchaType.php
index ffada26..0bea461 100755
--- a/Type/CaptchaType.php
+++ b/Type/CaptchaType.php
@@ -94,6 +94,7 @@ class CaptchaType extends AbstractType
 
     public function buildForm(FormBuilder $builder, array $options)
     {
+        $this->key = $builder->getForm()->getName();
         $builder->addValidator(
             new CaptchaValidator($this->session, $this->key)
         );
@@ -148,16 +149,20 @@ class CaptchaType extends AbstractType
 
     private function generateCaptchaValue()
     {
-        $charset = 'abcdefghijklmnopqrstuvwxyz0123456789';
-        $value = '';
-        $chars = str_split($charset);
+        if (!$this->session->has($this->key)) {
+            $value = '';
+            $charset = 'abcdefhjkmnprstuvwxyz23456789';
+            $chars = str_split($charset);
 
-        for ($i=0; $i<$this->length; $i++) {
-            $value.= $chars[array_rand($chars)];
+            for ($i=0; $i<$this->length; $i++) {
+                $value.= $chars[array_rand($chars)];
+            }
+
+            $this->session->set($this->key, $value);
+        } else {
+            $value = $this->session->get($this->key);
         }
 
-        $this->session->set($this->key, $value);
-
         return $value;
     }
 }
diff --git a/Validator/CaptchaValidator.php b/Validator/CaptchaValidator.php
index 47945c1..49707c9 100644
--- a/Validator/CaptchaValidator.php
+++ b/Validator/CaptchaValidator.php
@@ -38,9 +38,9 @@ class CaptchaValidator implements FormValidatorInterface
         if (!($code && $excepted_code && is_string($code) && is_string($excepted_code)
             && $this->niceize($code) == $this->niceize($excepted_code))) {
             $form->addError(new FormError('Bad code value'));
+        } else {
+            $this->session->remove($this->key);
         }
-
-        $this->session->remove($this->key);
     }
 
     /**